User Manual
TDS 520A, 524A, 540A, & 544A
Digitizing Oscilloscopes
070-8710-01
Please check for change information at the rear
of this manual.
First Printing: July 1993
Revised: November 1993
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WARRANTY
Tektronix warrants that this product will be free from defects in materials and workmanship for a period of three (3) years from
the date of shipment. If any such product proves defective during this warranty period, Tektronix, at its option, either will repair
the defective product without charge for parts and labor, or will provide a replacement in exchange for the defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the
warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for
packaging and shipping the defective product to the service center designated by Tektronix, with shipping charges prepaid.
Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the
Tektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any
other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting
from attempts by personnel other than Tektronix representatives to install, repair or service the product; b) to repair damage
resulting from improper use or connection to incompatible equipment; or c) to service a product that has been modified or
integrated with other products when the effect of such modification or integration increases the time or difficulty of servicing
the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY OTHER
WARRANTIES, EXPRESSED OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO REPAIR OR
REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR
BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE
VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
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German Postal Information
Certificate of the Manufacturer/Importer
We hereby certify that the TDS 520A, TDS 524A, TDS 540A, and TDS 544A Oscilloscopes and all
factory-installed options complies with the RF Interference Suppression requirements of Postal Regulation Vfg.
243/1991, Amended per Vfg. 46/1992
The German Postal Service was notified that the equipment is being marketed.
The German Postal Service has the right to re-test the series and to verify that it complies.
TEKTRONIX
Bescheinigung des Herstellers/Importeurs
Hiermit wird bescheinigt, daß der/die/das TDS 520A, TDS 524A, TDS 540A, and TDS 544A Oscilloscopes und
alle fabrikinstallierten Optionen in Übereinstimmung mit den Bestimmungen der Amtsblatt-Verfügung Vfg.
243/1991 und Zusatzverfügung 46/1992 funkentstört sind.
Der Deutschen Bundespost wurde das Inverkehrbringen dieses Gerätes angezeigt und die Berechtigung zur
Überprüfung der Serie auf Einhalten der Bestimmungen eingeräumt.
TEKTRONIX
NOTICE to the user/operator:
The German Postal Service requires that Systems assembled by the operator/user of this instrument must also
comply with Postal Regulation, Vfg. 243/1991, Par. 2, Sect. 1.
HINWEIS für den Benutzer/Betreiber:
Die vom Betreiber zusammengestellte Anlage, innerhalb derer dieses Gerät eingesetzt wird, muß ebenfalls den
Voraussetzungen nach Par. 2, Ziff. 1 der Vfg. 243/1991, genügen.
NOTICE to the user/operator:
The German Postal Service requires that this equipment, when used in a test setup, may only be operated if the
requirements of Postal Regulation, Vfg. 243/1991, Par. 2, Sect. 1.8.1 are complied with.
HINWEIS für den Benutzer/Betreiber:
Dieses Gerät darf in Meßaufbauten nur betrieben werden, wenn die Voraussetzungen des Par. 2, Ziff. 1. 8.1 der
Vfg. 243/1991 eingehalten werden.
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EC Declaration of Conformity
We
Tektronix Holland N.V.
Marktweg 73A
8444 AB Heerenveen
The Netherlands
declare under sole responsibility that the
TDS 520A, 524A, 540A, & 544A Digitizing Oscilloscopes
meet the intent of Directive 89/336/EEC for Electromagnetic Compatibility.
Compliance was demonstrated to the following specifications as listed in the official
Journal of the European Communities:
EN 50081–1 Emissions:
EN 55022
EN 55022
Radiated
Conducted
EN 60555–2 Power Harmonics
EN 50082–1 Immunity:
IEC 801–2
Electrostatic Discharge
RF Radiated
Fast Transients
IEC 801–3
IEC 801–4
IEC 801–5
Surge
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Welcome
This is the User Manual for the TDS Family Digitizing Oscilloscopes.
The Getting Started section familiarizes you with the operation of the digitizing
oscilloscope.
Operating Basics covers basic principles of the operation of the oscilloscope.
These articles help you understand why your instrument works the way it
does.
The Reference section teaches you how to perform specific tasks. See
page 3-1 for a complete list of tasks covered in that section.
The Appendices provide an options listing, an accessories listing, and other
useful information.
The following documents are related to the use or service of the digitizing
oscilloscope.
Related Manuals
The TDS Family Digitizing Oscilloscopes Programmer Manual (Tektronix
part number 070–8709–01) describes using a computer to control the
digitizing oscilloscope through the GPIB interface.
The TDS Family Option 05 Video Trigger Instruction Manual (Tektronix
part number 070–8748–00) describes use of the video trigger option (for
TDS oscilloscopes equipped with that option only).
The TDS 520A, 524A, 540A, 544A, & 644A Reference (Tektronix part
number 070–8711–01) gives you a quick overview of how to operate your
digitizing oscilloscope.
The TDS 520A, 524A, 540A, & 544A Performance Verification (Tektronix
part number 070–8712–01) tells how to verify the performance of the
digitizing oscilloscope.
The TDS 520A, 524A, 540A, & 544A Service Manual (Tektronix part
number 070–8713–01) provides information for maintaining and servicing
your digitizing oscilloscope to the module level.
TDS 620A, 640A, & 644A User Manual
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Welcome
In the Getting Started and Reference sections, you will find various proce-
dures which contain steps of instructions for you to perform. To keep those
instructions clear and consistent, this manual uses the following conventions:
Conventions
In procedures, names of front panel controls and menu labels appear in
boldface print.
Names also appear in the same case (initial capitals, all uppercase, etc.)
in the manual as is used on the oscilloscope front panel and menus. Front
panel names are all upper case letters, for example, VERTICAL MENU,
CH 1, etc.
Instruction steps are numbered. The number is omitted if there is only
one step.
When steps require that you make a sequence of selections using front
panel controls and menu buttons, an arrow ( ➞ ) marks each transition
between a front panel button and a menu, or between menus. Also,
whether a name is a main menu or side menu item is clearly indicated:
Press VERTICAL MENU ➞ Coupling (main) ➞ DC (side) ➞ Band-
width (main) ➞ 100 MHz (side).
Using the convention just described results in instructions that are graphi-
cally intuitive and simplifies procedures. For example, the instruction just
given replaces these five steps:
1. Press the front panel button VERTICAL MENU.
2. Press the main menu button Coupling.
3. Press the side-menu button DC.
4. Press the main menu button Bandwidth
5. Press the side menu button 100 MHz
Sometimes you may have to make a selection from a popup menu: Press
TRIGGER MENU ➞ Type (main) ➞ Edge (popup). In this example, you
repeatedly press the main menu button Type until Edge is highlighted in
the pop-up menu.
Welcome
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Table of Contents
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
v
Getting Started
Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Up for the Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 1: Displaying a Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 2: Multiple Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 3: Automated Measurements . . . . . . . . . . . . . . . . . . . . . . . .
Example 4: Saving Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1
1-3
1-6
1-7
1-13
1-17
1-23
Operating Basics
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scaling and Positioning Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . .
Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1
2-3
2-13
2-19
2-25
2-30
Reference
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acquisition Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Autoset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Color (TDS 524A & TDS 544A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cursor Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Delayed Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Display Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Edge Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fast Fourier Transforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1
3-3
3-10
3-12
3-17
3-22
3-28
3-34
3-38
TDS 520A, 524A, 540A, & 544A User Manual
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Table of Contents
File System (Optional on TDS 520A & TDS 540A) . . . . . . . . . . . . . .
Hardcopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Horizontal Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Limit Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logic Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Measurement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pulse Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Saving and Recalling Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Saving and Recalling Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signal Path Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vertical Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Waveform Differentiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Waveform Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Waveform Math . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-55
3-59
3-67
3-68
3-73
3-78
3-86
3-97
3-104
3-110
3-112
3-119
3-126
3-130
3-133
3-136
3-138
3-140
3-142
3-147
3-150
3-154
3-159
3-162
Appendices
Appendix A: Options and Accessories . . . . . . . . . . . . . . . . . . . . . . . .
Appendix B: Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix C: Packaging for Shipment . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix D: Factory Initialization Settings . . . . . . . . . . . . . . . . . . . .
A-1
A-9
A-23
A-25
Glossary
Index
Contents
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Safety
Please take a moment to review these safety precautions. They are provided
for your protection and to prevent damage to the digitizing oscilloscope. This
safety information applies to all operators and service personnel.
These two terms appear in manuals:
Symbols and Terms
statements identify conditions or practices that could result in
damage to the equipment or other property.
statements identify conditions or practices that could result in
personal injury or loss of life.
These two terms appear on equipment:
CAUTION indicates a personal injury hazard not immediately accessible
as one reads the marking or a hazard to property including the equipment
itself.
DANGER indicates a personal injury hazard immediately accessible as
one reads the marking.
This symbol appears in manuals:
Static-Sensitive Devices
These symbols appear on equipment:
DANGER
High Voltage
Protective
ground (earth)
terminal
ATTENTION
Refer to
manual
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Safety
Observe all of these precautions to ensure your personal safety and to pre-
vent damage to either the digitizing oscilloscope or equipment connected to it.
Specific Precautions
Power Source
The digitizing oscilloscope is intended to operate from a power source that will
not apply more than 250 V
between the supply conductors or between
RMS
either supply conductor and ground. A protective ground connection, through
the grounding conductor in the power cord, is essential for safe system
operation.
Grounding the Digitizing Oscilloscope
The digitizing oscilloscope is grounded through the power cord. To avoid
electric shock, plug the power cord into a properly wired receptacle where
earth ground has been verified by a qualified service person. Do this before
making connections to the input or output terminals of the digitizing oscillo-
scope.
Without the protective ground connection, all parts of the digitizing oscillo-
scope are potential shock hazards. This includes knobs and controls that may
appear to be insulators.
Use the Proper Power Cord
Use only the power cord and connector specified for your product. Use only a
power cord that is in good condition.
Use the Proper Fuse
To avoid fire hazard, use only the fuse specified in the parts list for your
product, matched by type, voltage rating, and current rating.
Do Not Remove Covers or Panels
To avoid personal injury, do not operate the digitizing oscilloscope without the
panels or covers.
Electric Overload
Never apply a voltage to a connector on the digitizing oscilloscope that is
outside the voltage range specified for that connector.
Do Not Operate in Explosive Atmospheres
The digitizing oscilloscope provides no explosion protection from static dis-
charges or arcing components. Do not operate the digitizing oscilloscope in
an atmosphere of explosive gases.
Safety
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Getting Started
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Product Description
Your Tektronix digitizing oscilloscope is a superb tool for acquiring, displaying,
and measuring waveforms. Its performance addresses the needs of both
benchtop lab and portable applications with the following features:
500 MHz maximum analog bandwidth.
1 Gigasample/second maximum digitizing rate (TDS 540A & 544A);
500 Megasamples/second maximum digitizing rate (TDS 520A & 524A).
Four-channel acquisition — the TDS 544A & 540A offer four full-featured
channels; the TDS 520A & 524A offer two full-featured channels and two
channels with limited vertical scale selections: 100 mV, 1 V, and 10 V.
Waveform Math — Invert a single waveform and add, subtract, multiply,
and divide two waveforms. On instruments with Option 2F: Advanced DSP
Math (standard on the TDS 524A & 544A), integrate or differentiate a
single waveform or perform an FFT (fast fourier transform) on a waveform
to display its magnitude or phase versus its frequency.
Eight-bit digitizers.
Up to 15,000-point record length per channel (50,000-point optional).
Full GPIB software programmability. Hardcopy output using RS-232 or
Centronics ports (Optional on TDS 520A & 540A) and the GPIB.
Complete measurement and documentation capability.
Intuitive graphic icon operation blended with the familiarity of traditional
horizontal and vertical knobs.
On-line help at the touch of a button.
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Product Description
Getting Started
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Start Up
Before you use the digitizing oscilloscope, ensure that it is properly installed
and powered on.
To ensure maximum accuracy for your most critical measurements, you
should know about signal path compensation.
Before You Begin
Signal Path Compensation
Be sure you compensate your oscilloscope for the surrounding temperature.
This action, called Signal Path Compensation (SPC), ensures maximum
possible accuracy for your most critical measurements. See Signal Path
Compensation on page 3-138 for a description of and operating information
on this feature.
To properly install and power on the digitizing oscilloscope, do the following:
Operation
Installation
1. Be sure you have the appropriate operating environment. Specifications
for temperature, relative humidity, altitude, vibrations, and emissions are
included in the TDS 520A, 524A, 540A, & 544A Performance Verification
manual (Tektronix part number 070–8712–01).
2. Leave space for cooling. Do this by verifying that the air intake and ex-
haust holes on the sides of the cabinet (where the fan operates) are free
of any airflow obstructions. Leave at least 5.1 cm (2 inches) free on each
side.
To avoid electrical shock, be sure that the power cord is discon-
nected before checking the fuse.
3. Check the fuse to be sure it is the proper type and rating (see Figure 1-1).
You can use either of two fuses. Each fuse requires its own cap (see
Table 1-1). The digitizing oscilloscope is shipped with the UL approved
fuse installed.
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Start Up
4. Check that you have the proper electrical connections. The digitizing
oscilloscope requires 90 to 250 VAC
63 Hz, and may require up to 300 W.
, continuous range, 47 Hz to
RMS
5. Connect the proper power cord from the rear-panel power connector (see
Figure 1-1) to the power system.
Power Connector
Principal Power Switch
Fuse
Figure 1-1: Rear Panel Controls Used in Start Up
Table 1-1: Fuse and Fuse Cap Part Numbers
Fuse
Fuse Part
Number
Fuse Cap Part
Number
.25 inch × 1.25 inch (UL 198.6, 3AG):
6 A FAST, 250 V.
159–0013–00
200–2264–00
5 mm × 20 mm (IEC 127): 5 A (T),
250 V.
159–0210–00
200–2265–00
Front Cover Removal
Remove the front cover by grasping its left and right edges and snapping it off
of the front subpanel. (When reinstalling, align and snap back on.)
Power On
1. Check that the rear-panel principal power switch is on (see Figure 1-1).
The principal power switch controls all AC power to the instrument.
2. If the oscilloscope is not powered on (the screen is blank), push the
front-panel ON/STBY button to toggle it on (see Figure 1-2).
The ON/STBY button controls power to most of the instrument circuits.
Power continues to go to certain parts even when this switch is set to
STBY.
Getting Started
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Start Up
Once the digitizing oscilloscope is installed, it is typical to leave the princi-
pal power switch on and use the ON/STBY button as the power switch.
ON/STBY Button
Figure 1-2: ON/STBY Button
Self Test
Check the self test results. The digitizing oscilloscope automatically performs
power-up tests each time it is turned on. It will come up with a display screen
that states whether or not it passed self test. (If the self test passed, the
status display screen will be removed after a few seconds.)
If the self test fails, call your local Tektronix Service Center. Depending on the
type of failure, you may still be able to use the oscilloscope before it is serv-
iced.
Power Off
Toggle the ON/STBY switch to turn off the oscilloscope.
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Setting Up for the Examples
All the examples use the same setup. Once you perform this setup, you do
not have to change the signal connections for any of the other examples.
Remove all probes and signal inputs from the input BNC connectors along the
lower right of the front panel. Then, using one of the probes supplied with the
digitizing oscilloscope, connect from the CH 1 connector to the PROBE
COMPENSATION connectors (see Figure 1-3).
Figure 1-3: Connecting a Probe for the Examples
Getting Started
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Example 1: Displaying a Waveform
In this first example you learn about resetting the digitizing oscilloscope,
displaying and adjusting a waveform, and using the autoset function.
All examples in the tutorial begin by resetting the digitizing oscilloscope to a
known factory default state. Reset the oscilloscope when you begin a new
task and need to “start fresh” with known default settings.
Resetting the
Digitizing
Oscilloscope
1. Press the save/recall SETUP button to display the Setup menu (Fig-
ure 1-4).
SETUP Button
Figure 1-4: SETUP Button Location
The digitizing oscilloscope displays main menus along the bottom of the
screen. Figure 1-5 shows the Setup main menu.
OK Confirm Factory Init
Menu Item and Button
Recall Factory Setup
Menu Item and Button
Figure 1-5: The Displayed Setup Menu
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Example 1: Displaying a Waveform
2. Press the button directly below the Recall Factory Setup menu item.
The display shows side menus along the right side of the screen. The
buttons to select these side menu items are to the right of the side menu.
Because an accidental instrument reset could destroy a setup that took a
long time to create, the digitizing oscilloscope asks you to verify the
Recall Factory Setup selection (see Figure 1-5).
3. Press the button to the right of the OK Confirm Factory Init side menu
item.
NOTE
This manual uses the following notation to represent the sequence
of selections you made in steps 1, 2 and 3: Press save/recall SET-
UP ➞ Recall Factory Setup (main) ➞ OK Confirm Factory Init
(side).
Note that a clock icon appears on screen. The oscilloscope displays this
icon when performing operations that take longer than several seconds.
4. Press SET LEVEL TO 50% (see Figure 1-6) to be sure the oscilloscope
triggers on the input signal.
SET LEVEL TO 50% Button
Figure 1-6: Trigger Controls
Getting Started
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Example 1: Displaying a Waveform
Figure 1-7 shows the display that results from the instrument reset. There are
several important points to observe:
Display Elements
The trigger level bar shows that the waveform is triggered at a level near
50% of its amplitude (from step 4).
The trigger position indicator shows that the trigger position of the wave-
form is located at the horizontal center of the graticule.
The channel reference indicator shows the vertical position of channel 1
with no input signal. This indicator points to the ground level for the
channel when its vertical offset is set to 0 V in the vertical menu; when
vertical offset is not set to 0 V, it points to the vertical offset level.
The trigger readout shows that the digitizing oscilloscope is triggering on
channel 1 (Ch1) on a rising edge, and that the trigger level is about
200–300 mV.
The time base readout shows that the main time base is set to a horizon-
tal scale of 500 s/div.
The channel readout indicates that channel 1 (Ch1) is displayed with DC
coupling. (In AC coupling, ~ appears after the volts/div readout.) The
digitizing oscilloscope always displays channel 1 at reset.
Trigger Level
Bar
Trigger Position Indicator
Channel Reference Indicator
Trigger Readout
Time Base Readout
Channel Readout
Figure 1-7: The Display After Factory Initialization
Right now, the channel, time base, and trigger readouts appear in the grati-
cule area because a menu is displayed. You can press the CLEAR MENU
button at any time to remove any menus and to move the readouts below the
graticule.
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Example 1: Displaying a Waveform
The display shows the probe compensation signal. It is a 1 kHz square wave
of approximately 0.5 V amplitude. You can adjust the size and placement of
the waveform using the front-panel knobs.
Adjusting the
Waveform Display
Figure 1-8 shows the main VERTICAL and HORIZONTAL sections of the
front panel. Each has SCALE and POSITION knobs.
1. Turn the vertical SCALE knob clockwise. Observe the change in the
displayed waveform and the channel readout at the bottom of the display.
Figure 1-8: The VERTICAL and HORIZONTAL Controls
2. Turn the vertical POSITION knob first one direction, then the other.
Observe the change in the displayed waveform. Then return the wave-
form to the center of the graticule.
3. Turn the horizontal SCALE knob one click clockwise. Observe the time
base readout at the bottom of the display. The time base should be set to
200 s/div now, and you should see two complete waveform cycles on
the display.
When you first connect a signal to a channel and display it, the signal dis-
played may not be scaled and triggered correctly. Use the autoset function
and you should quickly get a meaningful display.
Using Autoset
When you reset the digitizing oscilloscope, you see a clear, stable display of
the probe compensation waveform. That is because the probe compensation
signal happens to display well at the default settings of the digitizing oscillo-
scope.
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Example 1: Displaying a Waveform
1. To create an unstable display, slowly turn the trigger MAIN LEVEL knob
(see Figure 1-9) first one direction, then the other. Observe what happens
when you move the trigger level above the highest part of the displayed
waveform. Leave the trigger level in that untriggered state.
2. Press AUTOSET (see Figure 1-10) and observe the stable waveform
display.
MAIN LEVEL Knob
Figure 1-9: TRIGGER Controls
AUTOSET Button
Figure 1-10: AUTOSET Button Location
Figure 1-11 shows the display after pressing AUTOSET. If necessary, you can
adjust the waveform now by using the knobs discussed earlier in this exam-
ple.
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Example 1: Displaying a Waveform
Figure 1-11: The Display After Pressing Autoset
NOTE
If the corners on your displayed signal look rounded or pointed (see
Figure 1-12), then you may need to compensate your probe. The
Probe Compensation section on page 3-110 explains how to com-
pensate your probe.
Figure 1-12: Display Signals Requiring Probe Compensation
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Example 2: Multiple Waveforms
In this example you learn how to display and control more than one waveform
at a time.
The VERTICAL section of the front panel contains the channel selection
buttons. These are CH 1, CH 2, CH 3, CH 4, and MORE (Figure 1-13); on the
TDS 620A & 524A, they are CH 1, CH 2, AUX 1, AUX 2, and MORE.
Adding a Waveform
Figure 1-13: The Channel Buttons and Lights
Each of the channel (CH) buttons has a light above its label. Right now, the
CH 1 light is on. That light indicates that the vertical controls are set to adjust
channel 1.
The following steps add a waveform to the display.
1. If you are not continuing from the previous example, follow the instruc-
tions on page 1-6 under the heading Setting Up for the Examples.
2. Press SETUP ➞ Recall Factory Setup (main) ➞ OK Confirm Factory
Init (side).
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Example 2: Multiple Waveforms
3. Press AUTOSET.
4. Press CH 2.
The display shows a second waveform, which represents the signal on
channel 2. Since there is nothing connected to the CH 2 input connector,
this waveform is a flat line.
There are several other important things to observe:
The channel readout on the display now shows the settings for both
Ch1 and Ch2.
There are two channel indicators at the left edge of the graticule.
Right now, they overlap.
The light next to the CH 2 button is now on, and the CH 1 light is off.
Because the knobs control only one channel at a time, the vertical
controls are now set to adjust channel 2.
The trigger readout still indicates that the trigger is detecting trigger
events on Ch1. The trigger source is not changed simply by adding a
channel. (You can change the trigger source by using the TRIGGER
MENU button to display the trigger menu.)
5. Turn the vertical POSITION knob clockwise to move the channel 2 wave-
form up on the graticule. You will notice that the channel reference indica-
tor for channel 2 moves with the waveform.
6. Press VERTICAL MENU ➞ Coupling (main).
The VERTICAL MENU button displays a menu that gives you control
over many vertical channel parameters (Figure 1-14). Although there can
be more than one channel displayed, the vertical menu and buttons only
adjust the selected channel.
Each menu item in the Vertical menu displays a side menu. Right now,
the Coupling item in the main menu is highlighted, which means that the
side menu shows the coupling choices. At the top of the side menu, the
menu title shows the channel affected by the menu choices. That always
matches the lighted channel button.
7. Press (side) to toggle the selection to 50 . That changes the input
coupling of channel 2 from 1 M to 50 . The channel readout for chan-
nel 2 (near the bottom of the graticule) now shows an indicator.
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Example 2: Multiple Waveforms
Ch2 Reference Indicator
Side Menu Title
Figure 1-14: The Vertical Main Menu and Coupling Side Menu
Pressing a channel (CH) button sets the vertical controls to that channel. It
also adds the channel to the display if that waveform is not already displayed.
Changing Controls
to Another Channel
1. Press CH 1.
Observe that now the side menu title shows Ch1 (Figure 1-15), and that
the light above CH 1 is lighted. The highlighted menu item in the side
menu has changed from the 50 channel 2 setting to the 1 M imped-
ance setting of channel 1.
2. Press CH 2 ➞ (side) to toggle the selection to 1 M . That returns the
coupling impedance of channel 2 to its initial state.
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Example 2: Multiple Waveforms
Side Menu Title
Figure 1-15: The Menus After Changing Channels
Pressing the WAVEFORM OFF button removes the waveform for the current-
ly selected channel. If the waveform you want to remove is not already se-
lected, select that channel using the channel (CH) button.
Removing a
Waveform
1. Press WAVEFORM OFF (under the vertical SCALE knob).
Since the CH 2 light was on when you pressed the WAVEFORM OFF
button, the channel 2 waveform was removed.
The channel (CH) lights now indicate channel 1. Channel 1 has become
the selected channel. When you remove the last waveform, all the CH
lights are turned off.
2. Press WAVEFORM OFF again to remove the channel 1 waveform.
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Example 3: Automated Measurements
In this example you learn how to use the automated measurement system to
get numeric readouts of important waveform characteristics.
To use the automated measurement system, you must have a stable display
of your signal. Also, the waveform must have all the segments necessary for
the measurement you want. For example, a rise time measurement requires
at least one rising edge, and a frequency measurement needs at least one
complete cycle.
Displaying
Automated
Measurements
1. If you are not continuing from the previous example, follow the instruc-
tions on page 1-6 under the heading Setting Up for the Examples.
2. Press SETUP ➞ Recall Factory Setup (main) ➞ OK Confirm Factory
Init (side).
3. Press AUTOSET.
4. Press MEASURE to display the Measure main menu (see Figure 1-16).
Figure 1-16: Measure Main Menu and Select Measurement Side Menu
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Example 3: Automated Measurements
5. If it is not already selected, press Select Measrmnt (main). The readout
for that menu item indicates which channel the measurement will be
taken from. All automated measurements are made on the selected
channel.
The Select Measurement side menu lists some of the measurements that
can be taken on waveforms. There are many different measurements
available; up to four can be taken and displayed at any one time. Press-
ing the button next to the –more– menu item brings up the other mea-
surement selections.
6. Press Frequency (side). If the Frequency menu item is not visible, press
–more– (side) repeatedly until the Frequency item appears. Then press
Frequency (side).
Observe that the frequency measurement appears within the right side of
the graticule area. The measurement readout includes the notation Ch1,
meaning that that measurement is taken on the channel 1 waveform. (To
take a measurement on another channel, select that channel, and then
select the measurement.)
7. Press Positive Width (side) ➞ –more– (side) ➞ Rise Time (side) ➞
Positive Duty Cycle (side).
All four measurements are displayed. Right now, they cover a part of the
graticule area, including the displayed waveforms.
8. To move the measurement readouts outside the graticule area, press
CLEAR MENU (see Figure 1-17).
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Example 3: Automated Measurements
Press here to
remove menus
from screen.
Figure 1-17: Four Simultaneous Measurement Readouts
The Measure menu lets you remove measurements you no longer want
displayed. You can remove any one measurement, or you can remove them
all with a single menu item.
Removing
Measurement
Readouts
Press MEASURE ➞ Remove Measrmnt (main) ➞ Measurement 1, Mea-
surement 2, and Measurement 4 (side) to remove those measurements.
Leave the rise time measurement displayed.
By default, the measurement system will use the 10% and 90% levels of the
waveform for taking the rise time measurement. You can change these values
to other percentages or change them to absolute voltage levels.
Changing the
Measurement
Reference Levels
To examine the current values, press Reference Levels (main) ➞ High Ref
(side).
The General Purpose Knob
The general purpose knob, the large knob, is now set to adjust the high
reference level (Figure 1-18).
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Example 3: Automated Measurements
General Purpose Knob
Setting and Readout
General Purpose
Knob Icon
Highlighted Menu Item with
Boxed Readout Value
Figure 1-18: General Purpose Knob Indicators
There are several important things to observe on the screen:
The knob icon appears at the top of the screen. The knob icon indicates
that the general purpose knob has just been set to adjust a parameter.
The upper right corner of the screen shows the readout High Ref: 90%.
The High Ref side menu item is highlighted, and a box appears around
the 90% readout in the High Ref menu item. The box indicates that the
general purpose knob is currently set to adjust that parameter.
Turn the general purpose knob left and right, and then use it to adjust the high
level to 80%. That sets the high measurement reference to 80%.
Hint: To make large changes quickly with the general purpose knob, press the
SHIFT button before turning the knob. When the light above the SHIFT button
is on and the display says Coarse Knobs in the upper-right corner, the
general purpose knob speeds up significantly.
The Numeric Keypad
Any time the general purpose knob is set to adjust a numeric parameter, you
can enter the value as a number using the keypad instead of using the knob.
Always end the entry of a number by pressing the ENTER (
).
The numeric keypad also provides multipliers for engineering exponents, such
as m for milli, M for mega, and for micro. To enter these multiplier values,
press the SHIFT button, then press the multiplier.
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Example 3: Automated Measurements
1. Press Low Ref (side).
2. On the numeric keypad, press the 2, the 0, and the ENTER (
) but-
tons, which sets the low measurement reference to 20%. Observe that
the rise-time value has changed.
3. Press Remove Measrmnt (main) ➞ All Measurements (side). That
returns the display to its original state.
You have seen how to display up to four individual automated measurements
on screen. You can also pop up a display of almost all of the automated
measurements available in the Select Measrmnts side menus. This snap-
shot of measurements is taken on the waveform currently selected using the
channel selection buttons.
Displaying a
Snapshot of
Automated
Measurements
As when displaying individual measurements, you must have a stable display
of your signal, and that signal must have all the segments necessary for the
measurement you want.
1. Press Snapshot (main) to pop up a snapshot of all available single
waveform measurements. (See Figure 1-19).
Figure 1-19: Snapshot of Channel 1
The snapshot display includes the notation Ch 1, meaning that the mea-
surements displayed are taken on the channel 1 waveform. You take a
snapshot of a waveform in another channel by first selecting that channel
using the channel selection buttons.
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Example 3: Automated Measurements
The snapshot measurements do not continuously update. Snapshot
executes a one-time capture of all measurements and does not update
those measurements unless it is performed again.
2. Press Again (side) to do another snapshot and update the snapshot
measurements.
3. Press Remove Measrmnt (main) to remove the snapshot display. (You
can also press CLEAR MENU, but a new snapshot will be executed the
next time you display the Measure menu.)
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Example 4: Saving Setups
This example shows you how to save all the settings of the digitizing oscillo-
scope and how to recall the setup later to quickly re-establish the previously
saved state. The oscilloscope provides several storage locations where you
can save the setups. With the file system (optional on the TDS 620A &
TDS 640A), you can also save setups to a floppy disk.
Besides being able to save several complete setups, the digitizing oscillo-
scope remembers all the parameter settings when you power it off. That
feature lets you power on and continue where you left off without having to
reconstruct the state of the digitizing oscilloscope.
First, you need to create an instrument setup you want to save. The next
several steps establish a two-waveform display with a measurement on one
waveform. The setup created is complex enough that you might prefer not to
go through all these steps each time you want that display.
Saving a Setup
1. If you are not continuing from the previous example, follow the instruc-
tions on page 1-6 under the heading Setting Up for the Examples.
2. Press SETUP ➞ Recall Factory Setup (main) ➞ OK Confirm Factory
Init (side).
3. Press ➞ AUTOSET.
4. Press MEASURE ➞ Select Measrmnt (main) ➞ Frequency (side).
(Press the –more– side menu item if the Frequency selection does not
appear in the side menu.)
5. Press CH 2 ➞ CLEAR MENU.
6. Press SETUP ➞ Save Current Setup (main) to display the Setup main
menu (see Figure 1-20).
Note that the setup locations shown in the side menu are labeled
either user or factory. If you save your current setup in a location
labeled user, you will overwrite the user setup previously stored
there. If you work in a laboratory environment where several people
share the digitizing oscilloscope, check with the other users before
you overwrite their setup. Setup locations labeled factory have the
factory setup stored as a default and can be used to store current
setups without disturbing previously stored setups.
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Example 4: Saving Setups
Figure 1-20: Save/Recall Setup Menu
7. Press one of the To Setup side menu buttons to store the current instru-
ment settings into that setup location. Remember which setup location
you selected for use later.
There are more setup locations than can be listed at one time in the side
menu. The –more– side menu item gives you access to all the setup
locations.
Once you have saved a particular setup, you can change the settings as
you wish, knowing that you can come back to that setup at any time.
8. Press MEASURE ➞ Positive Width (side) to add that measurement to
the display.
To recall the setup, Press SETUP ➞ Recall Saved Setup (main) ➞ Recall
Recalling a Setup
Setup (side) for the setup location you used in the last exercise. The positive
width measurement is now removed from the display because you selected it
after you saved the setup.
This completes the tutorial. You can restore the default settings by pressing
SETUP ➞ Recall Factory Setup (main) ➞ OK Confirm Factory Init (side).
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Overview
This section describes the basic concepts of operating the digitizing oscillo-
scope. Understanding the basic concepts of your digitizing oscilloscope will
help you use it much more effectively.
The first part, At a Glance, quickly shows you how the oscilloscope is orga-
nized and gives some very general operating instructions. It also contains an
overview of all the main menus. This part includes:
Front Panel Map
Rear Panel Map
Display Map
Basic Menu Operation
Menu Map
The second part explains the following concepts:
The triggering system, which establishes conditions for acquiring sig-
nals. Properly set, triggers can convert displays from unstable jumbles or
blank screens into meaningful waveforms. See Triggering on page 2-13.
The acquisition system, which converts analog data into digital form.
See Acquisition on page 2-19.
The waveform scaling and positioning system, which changes the
dimensions of the waveform display. Scaling waveforms involves increas-
ing or decreasing their displayed size. Positioning means moving them
up, down, right, or left on the display. See Scaling and Positioning Wave-
forms on page 2-25.
The measurement system, which provides numeric information on the
displayed waveforms. You can use graticule, cursor, and automated
measurements. See Measurements on page 2-30.
At the end of each topic, For More Information will point you to sources where
more information can be found.
To explore these topics in more depth and to read about topics not covered in
this section, see Reference. Page 3-1 lists the topics covered.
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Overview
Operating Basics
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At a Glance
The At a Glance section contains illustrations of the display, the front and rear
panels, and the menu system. These will help you understand and operate
the digitizing oscilloscope. This section also contains a visual guide to using
the menu system.
Front Panel Map —
Left Side
File System,
page 3-55
(Optional on
TDS 640A &
TDS 620A)
Side Menu
Buttons,
page 2-7
ON/STBY Switch,
Main Menu Buttons,
page 2-7
CLEAR MENU
Removes Menus
from the Display
page 1-3
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At a Glance
Front Panel Map —
Right Side
Measurement System,
page 3-86
Color, page 3-12 (TDS 644A & TDS 524A)
Display Modes, page 3-28
Remote Communication, page 3-126
Cursor Measurements, page 3-17
Hardcopy, page 3-59
File System, page 3-55
Saving and Recalling
Waveforms, page 3-133
File System, page 3-55 (Optional
on TDS 620A & TDS 640A)
Acquisition Modes,
page 3-3
Cursor Measurements,
page 3-17
Saving and Recalling Setups,
page 3-130
Autoset, page 3-10
Help, page 3-67
Status, page 3-140
Selecting Channels,
page 3-136
WaveformMath,
page 3-159
VerticalControl,
page 3-147
Zoom,
page
3-162
Ground
Probe Compensation,
page 3-110
Horizontal Control,
page 3-68
Triggering, page 3-142
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At a Glance
Rear Panel Map
GPIB
Connector
page 3-126
Centronics Connector
(Optional on TDS 620A (Optional on TDS 620A
& TDS 640A) & TDS 640A)
RS-232 Connector
Principal Power Switch,
page 1-3
Fuse,
page 1-3
Serial Number
Power Connector,
page 1-3
Rear Panel
Connectors
(on TDS 540A &
544A only)
Security
Bracket
VGA Output
(Color with TDS 524A
& TDS 644A,
Monochrome with
TDS 620A &
SIGNAL OUTPUT –
(Provides CH3 analog signal output)
AUX TRIGGER INPUT –
(Provides auxiliary trigger signal input)
TDS 640A)
MAIN TRIGGER OUTPUT –
(Provides main trigger (TTL) output)
DELAYED TRIGGER OUTPUT –
(Provides delayed trigger (TTL) output)
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At a Glance
Display Map
When present, the general
purpose knob makes coarse
adjustments; when absent,
fine adjustments
The value entered with
the general purpose
knob
The acquisition
status, page 3-3
Trigger position (T),
page 3-142
The waveform
record icon
Indicates position of
vertical bar cursors in
the waveform record,
page 3-147
Shows what part of the waveform
record is displayed, page 3-68
Trigger level on
Cursor
measurements,
page 3-17
waveform (may be
an arrow at right
side of screen
instead of a bar)
The side menu
with choices of
specific actions
Channel level
and waveform
source
Trigger
parameters,
page 3-144
Vertical scale,
page 3-147
Horizontal scale
and time base
type, page 3-68
The main menu with
choices of major
actions
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At a Glance
To Operate a Menu
1. Press front-panel menu button.
(Press SHIFT first if button
label is blue.)
2. Press one of these buttons to
select from main menu.
3. Press one of these buttons to
select from side menu (if
displayed).
4. If side menu item has an ad-
justable value (shown in re-
verse video), adjust it with the
general purpose knob or
keypad.
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At a Glance
To Operate a Pop-Up
Menu
Press
to display pop-ups.
Press here to
remove menus
from screen.
Press it again
to make selection.
Alternatively, press
SHIFT first to make
selection in the opposite
direction.
A pop-up selection changes the
other main menu titles.
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At a Glance
Menu Map
Press these but-
tons:
To bring up these menus:
Acquire Menu
(see page 3-3)
Application Menu
(see the Programmer
manual for more details)
Cursor Menu
(see page 3-17)
Delayed Trigger Menu
(see page 3-22)
Display Menu – Color
(TDS 524A & TDS 544A)
(see page 3-12 )
Display Menu – Display
(TDS 524A & TDS 544A)
(see page 3-28)
Display Menu – Display
(TDS 520A & TDS 540A)
(see page 3-28)
Horizontal Menu
(see page 3-68)
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At a Glance
Press these button
Hardcopy Menu
(TDS 620A & TDS 640A)
(see page 3-59)
Hardcopy Menu
(TDS 644A & TDS 524A)
(see page 3-59)
Main Trigger Menu – Edge
(see page 3-34)
Main Trigger Menu – Logic
(see page 3-78)
Main Trigger Menu –Pulse
(see page 3-119)
Measure Menu
(see page 3-86)
More Menu
(see page 3-159)
Save/Recall Setup Menu
(see page 3-130)
Save/Recall Waveform Menu
(see page 3-133)
Status Menu
(see page 3-140)
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At a Glance
Press these buttons:
To bring up these menus:
Utility Menu – Calibration
(see page )
Utility Menu – Config
(see pages )
Utility Menu – Diagnostics
(see the Service manual)
Utility Menu – I/O – GPIB
(see page 3-126)
Utility Menu – I/O – RS232
(optional on TDS 620A &
TDS 640A) (see page 3-126)
Vertical Channel Menu
(see page 3-147)
Zoom Menu
(see page 3-162)
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At a Glance
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Triggering
This section describes the edge trigger of the main trigger system and ex-
plores, in a general sense, the topic of triggering. This oscilloscope also has
logic and pulse triggers in the main trigger system and a delayed trigger
system. They are described in Section 3.
Triggers determine when the digitizing oscilloscope starts acquiring and
displaying a waveform. They help create meaningful waveforms from unsta-
ble jumbles or blank screens (see Figure 2-1).
Triggered Waveform
Untriggered Waveforms
Figure 2-1: Triggered Versus Untriggered Displays
The trigger event establishes the time-zero point in the waveform record, and
all points in the record are located in time with respect to that point. The
digitizing oscilloscope continuously acquires and retains enough sample
points to fill the pretrigger portion of the waveform record (that part of the
waveform that is displayed before, or to the left of, the triggering event on
screen).
When a trigger event occurs, the digitizing oscilloscope starts acquiring
samples to build the posttrigger portion of the waveform record (displayed
after, or to the right of, the trigger event). Once a trigger is recognized, the
digitizing oscilloscope will not accept another trigger until the acquisition is
complete.
The basic trigger is the edge trigger. An edge trigger event occurs when the
trigger source (the signal that the trigger circuit monitors) passes through a
specified voltage level in a specified direction (the trigger slope).
You can derive your trigger from various sources.
Trigger Sources
Input channels — the most commonly used trigger source is any one of
the four input channels. The channel you select as a trigger source will
function whether it is displayed or not.
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Triggering
AC Line Voltage — this trigger source is useful when you are looking at
signals related to the power line frequency. Examples include devices
such as lighting equipment and power supplies. Because the digitizing
oscilloscope generates the trigger, you do not have to input a signal to
create the trigger.
Auxiliary Trigger — this trigger source is useful in digital design and
repair. For example, you might want to trigger with an external clock or
with a signal from another part of the circuit. To use the auxiliary trigger,
connect the external triggering signal to the Auxiliary Trigger input con-
nector on the oscilloscope rear panel (TDS 640A & TDS 644A only).
The digitizing oscilloscope provides three standard triggers for the main
trigger system: edge, pulse, and logic. Option 05 provides a video trigger. The
standard triggers are described in individual articles found in the Reference
section. A brief definition of each type follows:
Types
Edge — the “basic” trigger. You can use it with both analog and digital
test circuits. An edge trigger event occurs when the trigger source (the
signal the trigger circuit is monitoring) passes through a specified voltage
level in the specified direction (the trigger slope).
Pulse — special trigger primarily used on digital circuits. Three classes of
pulse triggers are width, runt, and glitch. Pulse triggering is available on
the main trigger only.
Logic — special trigger primarily used on digital logic circuits. You select
Boolean operators for the trigger sources. Triggering occurs when the
Boolean conditions are satisfied. There are two kinds of logic triggers,
state and pattern. (Logic triggers are available on the main trigger system
only.)
Video — (with option 05) special trigger used on video circuits. It helps
you investigate events that occur when a video signal generates a hori-
zontal or vertical sync pulse. Supported classes of video triggers include
NTSC, PAL, SECAM, and high definition TV signals.
The trigger mode determines how the oscilloscope behaves in the absence of
a trigger event. The digitizing oscilloscope provides two different trigger
modes, normal and automatic.
Trigger Modes
Normal — this trigger mode lets the oscilloscope acquire a waveform
only when it is triggered. If no trigger occurs, the oscilloscope will not
acquire a waveform. (You can push FORCE TRIGGER to force the
oscilloscope to make a single acquisition.)
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Triggering
Automatic — this trigger mode (auto mode) lets the oscilloscope acquire
a waveform even if a trigger does not occur. Auto mode uses a timer that
starts after a trigger event occurs. If another trigger event is not detected
before the timer times out, the oscilloscope forces a trigger anyway. The
length of time it waits for a trigger event depends on the time base set-
ting.
Be aware that auto mode, when forcing triggers in the absence of valid trig-
gering events, does not sync the waveform on the display. In other words,
successive acquisitions will not be triggered at the same point on the wave-
form; therefore, the waveform will appear to roll across the screen. Of course,
if valid triggers occur the display will become stable on screen.
Since auto mode will force a trigger in the absence of one, auto mode is
useful in observing signals where you are only concerned with monitoring
amplitude level. Although the unsynced waveform may “roll” across the
display, it will not freeze as it would in normal trigger mode. Monitoring of a
power supply output is an example of such an application.
When a trigger event is recognized, the oscilloscope disables the trigger
system until acquisition is complete. In addition, the trigger system remains
disabled during the holdoff period that follows each acquisition. You can set
holdoff time to help ensure a stable display.
Holdoff
For example, the trigger signal can be a complex waveform with many possi-
ble trigger points on it. Though the waveform is repetitive, a simple trigger
might get you a series of patterns on the screen instead of the same pattern
each time.
Digital pulse trains are good examples (see Figure 2-2). Each pulse looks like
any other, so many possible trigger points exist. Not all of these will result in
the same display. The holdoff period allows the digitizing oscilloscope to
trigger on the correct edge, resulting in a stable display.
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Triggering
Acquisition
Interval
Acquisition
Interval
Trigger Points
Trigger Level
Holdoff
Holdoff
Triggers are Not Recognized During Holdoff Time
Holdoff
Figure 2-2: Trigger Holdoff Time Ensures Valid Triggering
Holdoff is settable from 0% (minimum holdoff available) to 100% (maximum
available). To see how to set holdoff, see Mode & Holdoff on page 3-37. The
minimum and maximum holdoff varies with the horizontal scale. See Holdoff,
Variable, Main Trigger in the TDS 520A, 524A, 540A, & 544A Performance
Verification Manual, Section 2 on Specification, Typical Characteristics for
typical minimum and maximum values.
Trigger coupling determines what part of the signal is passed to the trigger
circuit. Available coupling types include AC, DC, Low Frequency Rejection,
High Frequency Rejection, and Noise Rejection:
Coupling
DC coupling passes all of the input signal. In other words, it passes both
AC and DC components to the trigger circuit.
AC coupling passes only the alternating components of an input signal.
(AC components above 10 Hz are passed if the source channel is in
1 M coupling; above 200 kHz are passed in 50 coupling.) It removes
the DC components from the trigger signal.
High frequency rejection removes the high frequency portion of the trig-
gering signal. That allows only the low frequency components to pass on
to the triggering system to start an acquisition. High frequency rejection
attenuates signals above 30 kHz.
Low frequency rejection does the opposite of high frequency rejection.
Low frequency rejection attenuates signals below 80 kHz.
Noise Rejection lowers trigger sensitivity. It requires additional signal
amplitude for stable triggering, reducing the chance of falsely triggering
on noise.
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Triggering
The adjustable trigger position defines where on the waveform record the
Trigger Position
trigger occurs. It lets you properly align and measure data within records. The
part of the record that occurs before the trigger is the pretrigger portion. The
part that occurs after the trigger is the posttrigger portion.
To help you visualize the trigger position setting, the top part of the display
has an icon indicating where the trigger occurs in the waveform record. You
select in the Horizontal menu what percentage of the waveform record will
contain pretrigger information.
Many users find displaying pretrigger information a valuable troubleshooting
technique. For example, if you are trying to find the cause of an unwanted
glitch in your test circuit, it may prove valuable to trigger on the glitch and
make the pretrigger period large enough to capture data before the glitch. By
analyzing what happened before the glitch, you may uncover clues about the
source of the glitch.
The slope control determines whether the oscilloscope finds the trigger point
on the rising or the falling edge of a signal (see Figure 2-3).
Slope and Level
You set trigger slope by selecting Slope in the Main Trigger menu and then
selecting from the rising or falling slope icons in the side menu that appears.
The level control determines where on that edge the trigger point occurs (see
Figure 2-3).
Positive-Going Edge
Negative-Going Edge
Trigger Level Can be
Adjusted Vertically
Trigger Slope Can be Positive or Negative
Figure 2-3: Slope and Level Controls Help Define the Trigger
The digitizing oscilloscope lets you set the main trigger level with the trigger
MAIN LEVEL knob.
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Triggering
As mentioned earlier in this section there is also a delayed trigger system that
provides an edge trigger (no pulse or logic triggers). When using the delayed
time base, you can also delay the acquisition of a waveform for a user-speci-
fied time or a user-specified number of delayed trigger events (or both) after a
main trigger event.
Delayed Trigger
See Delayed Triggering, on page 3-22.
See Edge Triggering, on page 3-34.
See Horizontal Controls, on page 3-68.
See Logic Triggering, on page 3-78.
See Pulse Triggering, on page 3-119.
See Triggering, on page 3-142.
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Acquisition
Acquisition is the process of sampling the analog input signal, converting it
into digital data, and assembling it into a waveform record. The oscilloscope
creates a digital representation of the input signal by sampling the voltage
level of the signal at regular time intervals (Figure 2-4).
+5.0 V
+5.0 V
0 V
0 V
0 V
0 V
–5.0 V
–5.0 V
Input Signal
Sampled
Points
Digital
Values
Figure 2-4: Acquisition: Input Analog Signal, Sample, and Digitize
The sampled points are stored in memory along with corresponding timing
information. You can use this digital representation of the signal for display,
measurements, or further processing.
You specify how the digitizing oscilloscope acquires data points and as-
sembles them into the waveform record.
The trigger point marks time zero in a waveform record. All record points
before the trigger event make up the pretrigger portion of the the waveform
record. Every record point after the trigger event is part of the posttrigger
portion. All timing measurements in the waveform record are made relative to
the trigger event.
Sampling and
Digitizing
Each time it takes a sample, the oscilloscope digitizer produces a numeric
representation of the signal. The number of samples may be larger than the
number of points in your waveform record. In fact, the oscilloscope may take
several samples for each record point (Figure 2-5).
Interval for One Waveform Record Point
Samples For a
Record Point
Figure 2-5: Several Points May be Acquired for Each Point Used
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Acquisition
The digitizer can use the extra samples to perform additional processing,
such as averaging or looking for minimum and maximum values.
The digitizing oscilloscope creates a waveform record containing a user-spe-
cified number of data points. Each record point represents a certain voltage
level that occurs a determined amount of time from the trigger event.
Record Length
The number of points that make up the waveform record is defined by the
record length. You can set the record length in the Horizontal menu. The
digitizing oscilloscope provides record lengths of 500, 1000, 2500, 5000, and
15000 points.
You can order option 1M that provides a maximum record length of 50,000
points. That option is available only at the time of original purchase; it cannot
be installed later.
Sampling
Sampling is the process of converting the analog input signal to digital data
for display and processing (see Figure 2-6). The two general methods of
sampling are real-time and equivalent-time.
Real-Time Sampling — In real-time sampling, the oscilloscope digitizes all
the points it acquires after one trigger event (see Figure 2-6). Use real-time
sampling to capture single-shot or transient events.
Record Points
Sampling Rate
Figure 2-6: Real-Time Sampling
Two factors that affect real-time sampling on the digitizing oscilloscope are
interleaving and interpolation.
Interleaving refers to the ability of the digitizing oscilloscope to attain higher
digitizing speeds by combining the efforts of several digitizers. For example, if
you want to digitize on all channels at one time (four on the TDS 644A and
TDS 640A and two on the TDS 524A and TDS 620A), each of those channels
can digitize at a maximum real-time speed of 250 Megasamples/second (per
channel).
If you use two channels, the TDS 644A and TDS 640A oscilloscopes can
combine the efforts of two digitizers to each channel and acquire at 500
Megasamples/second (per channel).
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Acquisition
If you focus on only one channel at the maximum possible real-time rate, the
TDS 524A and TDS 620A oscilloscopes can acquire at 500 Megasamples/
second using both its digitizers, while the TDS 644A and TDS 640A oscillo-
scopes can combine all four digitizers and acquire at 1 Gigasample/second.
Depending on how many channels you are using and the speed of the time
base, at some point the digitizing oscilloscope will not be able to get enough
samples to create a waveform record. (See the discussion on page 2-22 for
more details about when that happens.) At that point, the digitizing oscillo-
scope will create the waveform record in one of two ways depending on
whether you have limited the oscilloscope to real-time sampling or enabled
equivalent-time sampling (you make that choice in the Acquisition menu).
If you have restricted it to real-time sampling, the digitizing oscilloscope uses
a process called interpolation to create the intervening points in the waveform
record. There are two options for interpolation: linear or sin(x)/x.
Linear interpolation computes record points between actual acquired samples
by using a straight line fit. It assumes all the interpolated points fall in their
appropriate point in time on that straight line. Linear interpolation is useful for
many waveforms such as pulse trains.
Sin(x)/x interpolation computes record points using a curve fit between the
actual values acquired. It assumes all the interpolated points fall along that
curve. That is particularly useful when acquiring more rounded waveforms
such as sine waves. Actually, it is appropriate for general use, although it may
introduce some overshoot or undershoot in signals with fast rise times.
NOTE
When using either type of interpolation, you may wish to set the
display style so that the real samples are displayed intensified
relative to the interpolated samples. The instructions under Display
Style on page 3-28 explain how to turn on intensified samples.
Equivalent-Time Sampling — The digitizing oscilloscope only uses
equivalent-time sampling if you have enabled the equivalent-time option in the
Acquisition menu and the oscilloscope is not able to get enough samples with
which to create a waveform record.
In equivalent-time (ET) sampling the oscilloscope acquires samples over
many repetitions of the event (Figure 2-7). It should only be used on repetitive
signals.
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Acquisition
Record Points
1st Acquisition Cycle
2nd Acquisition Cycle
3rd Acquisition Cycle
nth Acquisition Cycle
Figure 2-7: Equivalent-Time Sampling
The oscilloscope takes a few samples with each trigger event and eventually
constructs a waveform record using the samples from multiple acquisitions.
That feature lets you accurately acquire signals with frequencies much higher
than the digitizing oscilloscope real-time bandwidth.
The digitizing oscilloscope uses a type of equivalent-time sampling called
random equivalent-time sampling. Although the samples are taken sequential-
ly in time, they are random with respect to the trigger. That is because the
oscilloscope sample clock runs asynchronously with respect to the input
signal and the signal trigger. The oscilloscope takes samples independent of
the trigger position and displays them based on the time difference between
the sample and the trigger.
The sampling speeds and the number of channels you choose affect the
mode the digitizing oscilloscope uses to sample waveforms. Basically, if the
time base is 200 ns or slower, the digitizing oscilloscope uses real-time sam-
pling for creating waveform records when Fit to Screen is off.
Selecting Sampling
Mode
When the time base is faster than 50 ns, the digitizing oscilloscope creates
waveform records using equivalent-time sampling or interpolation. For speeds
between 200 ns and 20 ns, the digitizing oscilloscope creates waveform
records differently depending on the number of input channels and type of
oscilloscope you are using (see Table 2-1).
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Acquisition
Table 2-1: Sampling Mode Selection —
100 ns/Div to 50 ns/Div (When Fit to Screen is Off)
Instrument and
Number of Channels
100 ns/Div
Real-time
Real-time
50 ns/Div
TDS 544A & 540A,
any 1 channel
Real-time
TDS 544A & 540A,
any 2 channels
Equivalent-time or
interpolated real-time
TDS 544A & 540A,
3 or more channels
Equivalent-time or
interpolated real-time
Equivalent-time or
interpolated real-time
TDS 524A & 520A,
any 1 channel
Real-time
Equivalent-time or
interpolated real-time
TDS 524A & 520A, any Equivalent-time or
2 channels interpolated real-time
Equivalent-time or
interpolated real-time
The digitizing oscilloscope supports five acquisition modes.
Acquisition Modes
Sample
Peak Detect
Hi Res
Envelope
Average
Sample acquisition mode, which acquires in real time, is the mode most
commonly used. You can read about Sample and the other acquisition modes
in Acquisition Modes, beginning on page 3-3.
Bandwidth refers to the range of frequencies that an oscilloscope can acquire
and display accurately (that is, with less than 3 dB attenuation).
Bandwidth
Coupling
You can set different bandwidths with the digitizing oscilloscope. Lower band-
width settings let you eliminate the higher frequency components of a signal.
The TDS 600A series offers Full (500 MHz), 100 MHz, and 20 MHz band-
width settings.
You can couple your input signal to the digitizing oscilloscope three ways. You
can choose between AC, DC, or Ground (GND). You can also set the input
impedance.
DC coupling shows both the AC and DC components of an input signal.
AC coupling shows only the alternating components of an input signal.
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Acquisition
Ground (GND) coupling disconnects the input signal from the acquisition.
Input impedance lets you select either 1 M or 50
impedance.
NOTE
If you select 50 impedance with AC coupling, the digitizing oscillo-
scope will not accurately display frequencies under 200 kHz.
See Scaling and Positioning Waveforms, on page 2-25.
See Acquisition Modes, on page 3-3.
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Scaling and Positioning Waveforms
Scaling and positioning waveforms means increasing or decreasing their
displayed size and moving them up, down, right, and left on the display.
Two display icons, the channel reference indicator and the record view, help
you quickly see the position of the waveform in the display (see Figure 2-8).
The channel reference icon points to the ground of the waveform record when
offset is set to 0 V. This is the point about which the waveform contracts or
expands when the vertical scale is changed. The record view, at the top of the
display, indicates where the trigger occurs and what part of the waveform
record is displayed.
Record View
Channel Reference Icon
Original Position
Positioned Vertically
Positioned Horizontally
Original Scale
Scaled
Scaled Horizontally
Vertically
Figure 2-8: Scaling and Positioning
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Scaling and Positioning Waveforms
You can adjust the vertical position of the selected waveform by moving it up
or down on the display. For example, when trying to compare multiple wave-
forms, you can put one above another and compare them, or you can overlay
the two waveforms on top of each other. To move the selected waveform turn
the vertical POSITION knob.
Vertical System
You can also alter the vertical scale. The digitizing oscilloscope shows the
scale (in volts per division) for each active channel toward the bottom left of
the display. As you turn the vertical SCALE knob clockwise, the value de-
creases resulting in higher resolution because you see a smaller part of the
waveform. As you turn it counter-clockwise the scale increases allowing you
to see more of the waveform but with lower resolution.
Besides using the position and scale knobs, you can set the vertical scale and
position with exact numbers. You do that with the Vertical menu Fine Scale
and Position selections and the general purpose knob and/or the keypad.
Offset
Vertical offset changes where the channel reference indicator is shown with
respect to the graticule. Offset adds a voltage to the reference indicator
without changing the scale. That feature allows you to move the waveform up
and down over a large area without decreasing the resolution.
Offset is useful in cases where a waveform has a DC bias. One example is
looking at a small ripple on a power supply output. You may be trying to look
at a 100 mV ripple on top of a 15 V supply. The range available with offset
can prove valuable as you try to move and scale the ripple to meet your
needs.
Adjusting the horizontal position of waveforms moves them right or left on the
display. That is useful when the record length of the waveform is so large
(greater than 500 points) that the digitizing oscilloscope cannot display the
entire waveform record at one time. You can also adjust the scale of the
waveform. For example, you might want to see just one cycle of a waveform
to measure the overshoot on its rising edge.
Horizontal System
You adjust the horizontal scale of the displayed waveform records using the
horizontal SCALE knob and the horizontal position using the horizontal
POSITION knob.
The digitizing oscilloscope shows the actual scale in the bottom right of the
display. The scale readout shows the time per division used. Since all live
waveforms use the same time base, the digitizing oscilloscope only displays
one value for all the active channels.
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Scaling and Positioning Waveforms
Aliasing
When aliasing happens, you see a waveform with a frequency lower than the
actual waveform being input or a waveform is not stable even though the light
next to TRIG’D is lit. Aliasing occurs because the oscilloscope cannot sample
the signal fast enough to construct an accurate waveform record (Figure 2-9).
Actual High-Frequency Waveform
Apparent Low-Frequency
Waveform Due to Aliasing
Sampled Points
Figure 2-9: Aliasing
One simple way to check for aliasing is to slowly change the horizontal scale
(time per division setting). If the shape of the displayed waveform changes
drastically, you may have aliasing.
In order to represent a signal accurately and avoid aliasing, you must sample
the signal more than twice as fast as the highest frequency component. For
example, a signal with frequency components of 500 MHz would need to be
sampled at a rate faster than 1 Gigasamples/second.
There are various ways to prevent aliasing. Try adjusting the horizontal scale,
or simply press the AUTOSET button. You can also counteract some aliasing
by changing the acquisition mode in the Acquisition menu. For example, if
you are using the sample mode and suspect aliasing, you may want to
change to the peak detect mode. Since the peak detect mode searches for
samples with the highest and lowest values, it can detect faster signal compo-
nents over time.
Delayed Time Base
You can set a main time base and a delayed time base. Each time base has
its own trigger. There are two types of delayed time base acquisitions. Each
type is based on its triggering relationship to the main time base. These are
delayed runs after main and delay triggerable (after time, events, or both)
acquisitions.
The delayed time base is useful in displaying events that follow other events.
See Triggering on page 2-13 for more information on the delayed trigger.
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Scaling and Positioning Waveforms
FastFrameTM
TM
You can define and enable FastFrame (also called “segmented memory”)
on the TDS 600A. This feature lets you capture multiple acquisitions in the
acquisition memory of a single channel. Figure 2-10 shows how FastFrame
combines the desired captured records into one larger record. For example,
FastFrame would let you store 10 records of 500 samples each into one
record with a 5000 sample length.
Real Time
Fast Frame
Figure 2-10: Fast Frame
You can use zoom to see more detail without changing the acquired signal.
When you press the ZOOM button, a portion of the waveform record can be
expanded or compressed on the display, but the record points stay the same.
Zoom
Zoom is very useful when you wish to temporarily expand a waveform to
inspect small feature(s) on that waveform. For example, you might use zoom
to temporarily expand the front corner of a pulse to inspect its aberrations.
Use zoom to expand it horizontally and vertically. After you are finished, you
can return to your original horizontal scale setting by pressing one menu
button. (The zoom feature is also handy if you have acquired a waveform
while using the fastest time per division and want to further expand the wave-
form horizontally.)
Autoset lets you quickly obtain a stable waveform display. It automatically
adjusts a wide variety of settings including vertical and horizontal scaling.
Other settings affected include trigger coupling, type, position, slope, and
mode and display intensities. Autoset on page 3-10 describes in detail what
autoset does.
Autoset
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Scaling and Positioning Waveforms
See Autoset, on page 3-10.
For More
Information
See Delayed Triggering, on page 3-22.
See Horizontal Control, on page 3-68.
See Vertical Control, on page 3-147.
See Zoom, on page 3-162.
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Measurements
The digitizing oscilloscope not only displays graphs of voltage versus time, it
also can help you measure the displayed information (see Figure 2-11).
Cursor
Automated
Readouts
Measurements
Graticule
Ch 1
Frequency
100 MHz
Ch 1 Period
10 ns
Cursors
Figure 2-11: Graticule, Cursor and Automated Measurements
The oscilloscope provides three measurement classes. They are: automated,
cursors, and graticule measurements.
Measurement
Sources
Automated Measurements
You make automated measurements merely by pressing a few buttons. The
digitizing oscilloscope does all the calculating for you. Because these mea-
surements use the waveform record points, automated measurements are
more accurate than cursor or graticule measurements.
Press the MEASURE button for the automated measurement menus. These
menus let you make amplitude (typically in volts; sometimes in %), time
(typically in seconds or hertz), and area (in volt-seconds) measurements. You
can select and display up to four measurements at a time. (See Table 3-5 on
page 3-86 for a list of all the automatic measurements and their definitions.)
You can make automated measurements on the entire waveform record or
just on a specific part. The gating selection in the Measurement menu lets
you use the vertical cursors to limit the measurement to a section of the
waveform record.
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Measurements
The snapshot selection in the Measurement menu lets you display almost all
of the measurements at once. You can read about snapshot under Snapshot
of Measurements, on page 3-95.
Automated measurements use readouts to show measurement status. These
readouts are updated as the oscilloscope acquires new data or if you change
settings.
Cursor Measurements
Cursors are fast and easy-to-understand measurements. You take measure-
ments by moving the cursors and reading their numeric values from the on
screen readouts, which update as you adjust the position of the cursors.
Cursors appear in pairs. One cursor is active and the other inactive. You
move the active cursor (the solid line) using the general purpose knob. The
SELECT button lets you select (toggle) which cursor bar is active or inactive.
The inactive cursor is a dashed line on the display.
To get the cursor menu, press the CURSOR button. There are three kinds of
cursors available in that menu:
Horizontal bar cursors measure vertical parameters (typically volts).
Vertical bar cursors measure horizontal parameters (typically time or
frequency).
Paired cursors measure both vertical parameters (typically volts) and
horizontal parameters (typically time or frequency).
There are also two modes for cursor operation available in the cursor me-
nu — independent and tracking (See Figure 2-12).
Independent Mode
Tracking Mode
Only Selected Cursor
Moves
Both Cursors Move
in Tandem
Figure 2-12: Cursor Modes
Independent mode cursors operate as was earlier described; that is, you
move one cursor at a time (the active cursor) using the general purpose
knob, and you use the SELECT button to toggle which cursor is active.
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Measurements
Tracking mode cursors operate in tandem: you move both cursors at the
same time using the general purpose knob. To adjust the solid cursor
relative to the dashed cursor, you push the SELECT button to suspend
cursor tracking and use the general purpose knob to make the adjust-
ment. A second push toggles the cursors back to tracking.
You can read more detailed information about how to use cursors in Cursor
Measurements, beginning on page 3-17.
Graticule Measurements
Graticule measurements provide you with quick, visual estimates. For exam-
ple, you might look at a waveform amplitude and say “it is a little more than
100 mV.”
You can perform simple measurements by counting the number of major and
minor graticule divisions involved and multiplying by the scale factor.
For example, if you counted five major vertical graticule divisions between the
minimum and maximum values of a waveform and knew you had a scale
factor of 100 mV/division, then you could easily calculate your peak-to-peak
voltage:
5 divisions × 100 mV/division = 500 mV.
NOTE
AUX 1 and AUX 2 (TDS 524A & TDS 620A) can not be set to the
volts per division needed to match video graticules.
When you select the NTSC graticule, the volts per division of all selected
channels is set to 143 mV/div (152 mV/div for PAL) where the divisions are
those of the conventional graticule, not the divisions of the video graticules.
For NTSC, the actual grid lines represent 10 IRE, and for PAL the lines are
100 mV apart.
See Appendix B: Algorithms, on page A-9, for details on how the digitizing
oscilloscope calculates each automatic measurement.
For More
Information
See Cursor Measurements, on page 3-17, for more information on cursor
measurements.
See Measurement System, on page 3-86, for more information on automatic
measurements.
See Tutorial Example 3: Automated Measurements, on page 1-17, for more
information on automatic measurements.
See Waveform Math, on page 3-159, for using cursors to measure math
waveforms.
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Reference
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Overview
This section describes the details of operating the digitizing oscilloscope. It
contains an alphabetical list of tasks you can perform with the digitizing
oscilloscope. Use this section to answer specific questions about instrument
operation. These tasks include:
Acquisition Modes
Autoset
Probe Cal
Probe Compensation
Probe Selection
Color
Cursor Measurements
Delayed Triggering
Display Modes
Edge Triggering
Pulse Triggering
Remote Communication
Saving and Recalling Setups
Saving and Recalling Wave-
forms
Fast Fourier Trans-
forms
Selecting Channels
Signal Path Compensation
Status
File System
Hardcopy
Help
Triggering
Horizontal Control
Limit Testing
Logic Triggering
Measurement System
Vertical Control
Waveform Differentiation
Waveform Integration
Waveform Math
Zoom
Many of these tasks list steps you perform to accomplish the task. You should
read Conventions on page ii of Welcome before reading about these tasks.
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Overview
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Acquisition Modes
The acquisition system has several options for converting analog data into
digital form. The Acquisition menu lets you determine the acquisition mode,
whether or not to permit equivalent time sampling, and how to start and stop
acquisitions.
The digitizing oscilloscope supports five acquisition modes.
Description of Modes
Sample
Peak Detect
Hi Res
Envelope
Average
The Sample, Peak Detect, and Hi Res modes operate in real-time on a single
trigger event, provided the digitizing oscilloscope can acquire enough samples
for each trigger event. Envelope and Average modes operate on multiple
acquisitions. The digitizing oscilloscope averages or envelopes several wave-
forms on a point-by-point basis.
Figure 3-1 illustrates the different modes and lists the benefits of each. It will
help you select the appropriate mode for your application.
Sample Mode
In Sample mode, the oscilloscope creates a record point by saving the first
sample (of perhaps many) during each acquisition interval. (An acquisition
interval is the time covered by the waveform record divided by the record
length.) This is the default mode.
Peak Detect Mode
Peak Detect mode alternates between saving the highest sample in one
acquisition interval and lowest sample in the next acquisition interval. Peak
Detect mode only works with real-time, non-interpolated sampling.
If you set the time base so fast that it requires real-time interpolation or
equivalent-time sampling, the mode automatically changes from Peak Detect
to Sample, although the menu selection will not change.
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Acquisition Modes
Samples Acquired in Four
Acquisition Intervals
Acquisition
Mode
Displayed
Record Points
Waveform
Drawn on CRT
Interval 1
2
3
4
Sample
Uses first sample
in interval
Use for fastest acquisition rate.
This is the default mode.
Peak Detect
Uses highest and lowest
samples in two intervals
Use to reveal aliasing and for glitch detection.
Provides the benefits of enveloping with the
speed of a single acquisition.
Hi Res
Calculates average of all
samples in interval
Use to reduce apparent noise.
Provides the benefits of averaging
with the speed of a single acquisition.
Acquisition
Mode
Waveform
Drawn on CRT
Three Acquisitions from One Source
2
Acquisition
3
1
Envelope
Finds highest and
lowest record points over
many acquisitions
Uses Peak Detect Mode for Each Acquisition
Use to reveal variations
in the signal across time.
Average
Calculates average value for
each record point over many
acquisitions
Uses Sample Mode for Each Acquisition
Use to reduce apparent noise
in a repetitive signal.
Figure 3-1: How the Acquisition Modes Work
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Acquisition Modes
Hi Res Mode
In Hi Res mode, the digitizing oscilloscope averages all samples taken during
an acquisition interval to create a record point. That average results in a
higher-resolution, lower-bandwidth waveform.
This mode only works with real-time, non-interpolated sampling. If you set the
time base so fast that it requires real-time interpolation or equivalent-time
sampling, the mode automatically becomes Sample, although the menu
selection will not change.
A key advantage of Hi Res is its potential for increasing resolution regardless
of the input signal. Table 3-1 and the equations shown below illustrate how
you can obtain up to 15 significant bits with Hi res mode. Note that the resolu-
tion improvements are limited to speeds slower than 400 ns/div. Also, resolu-
tions above 15 bits are not allowed by internal hardware and computation
limitations.
Si = Sampling Interval for TDS 500A = 4 ns
t = Sample Interval =
= = 100 ns
Nd = Number of points per decimation interval = = 25
Resolution Enhancement (bits) = 2 extra bits
Table 3-1: Additional Resolution Bits
Time Base Speed
400 ns and faster
1 s to 2 s
Bits of Resolution
8 bits
9 bits
5 s to 10 s
20 s to 50 s
100 s to 200 s
500 s
10 bits
11 bits
12 bits
13 bits
1 ms to 2 ms
14 bits
5 ms and slower
15 bits
Envelope Mode
Envelope mode lets you acquire and display a waveform record that shows
the extremes in variation over several acquisitions. You specify the number of
acquisitions over which to accumulate the data. The oscilloscope saves the
highest and lowest values in two adjacent intervals similar to the Peak Detect
mode. But Envelope mode, unlike Peak Detect, gathers peaks over many
trigger events.
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Acquisition Modes
After each trigger event, the oscilloscope acquires data and then compares
the min/max values from the current acquisition with those stored from pre-
vious acquisitions. The final display shows the most extreme values for all the
acquisitions for each point in the waveform record.
Average Mode
Average mode lets you acquire and display a waveform record that is the
averaged result of several acquisitions. This mode reduces random noise.
The oscilloscope acquires data after each trigger event using Sample mode.
It then averages the record point from the current acquisition with those
stored from previous acquisitions.
The acquisition readout at the top of the display (Figure 3-2) shows the state
of the acquisition system (running or stopped). The “running” state shows the
sample rate and acquisition mode. The “stopped” state shows the number of
acquisitions acquired since the last stop or major change.
Acquisition Readout
Acquisition Readout
Figure 3-2: Acquisition Menu and Readout
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Acquisition Modes
To bring up the acquisition menu (Figure 3-2) press SHIFT ACQUIRE MENU.
Operation
Acquisition Mode
To choose how the digitizing oscilloscope will create points in the waveform
record:
Press SHIFT ACQUIRE MENU ➞ Mode (main) ➞ Sample, Peak Detect, Hi
Res, Envelope, or Average (side).
When you select Envelope or Average, you can enter the number of wave-
form records to be enveloped or averaged using the keypad or the general
purpose knob.
NOTE
If you selected the longest record length available in the Horizontal
menu, then you cannot select Hi Res as your acquisition mode. This
is because Hi Res mode uses twice the acquisition memory that the
other acquisition modes use. If Hi Res and the longest horizontal
record length were allowed to be selected at the same time, the
oscilloscope would run out of memory.
Repetitive Signal
To limit the digitizing oscilloscope to real-time sampling or let it choose be-
tween real-time or equivalent-time sampling:
Press SHIFT ACQUIRE MENU ➞ Repetitive Signal (main) ➞ ON or OFF
(side).
ON (Enable ET) uses both the real time and the equivalent time features
of the digitizing oscilloscope.
OFF (Real Time Only) limits the digitizing oscilloscope to real time
sampling. If the digitizing oscilloscope cannot accurately get enough
samples for a complete waveform, the oscilloscope will use the interpola-
tion method selected in the display menu to fill in the missing record
points. That is, it will use either the linear or sin(x)/x interpolation algo-
rithm.
See Acquisition on page 2-19 for details about sampling.
Stop After
You can choose to acquire exactly one waveform sequence or to acquire
waveforms continuously under manual control.
Press SHIFT ACQUIRE MENU ➞ Stop After (main) ➞ RUN/STOP button
only, Single Acquisition Sequence, or Limit Test Condition Met (side)
(see Figure 3-3).
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Acquisition Modes
Figure 3-3: Acquire Menu — Stop After
RUN/STOP button only (side) lets you start or stop acquisitions by
toggling the RUN/STOP button. Pressing the RUN/STOP button once will
stop the acquisitions. The upper left hand corner in the display will say
Stopped and show the number of acquisitions. If you press the button
again, the digitizing oscilloscope will resume taking acquisitions.
Press Single Acquisition Sequence (side). That selection lets you run a
single sequence of acquisitions by pressing the RUN/STOP button. In
Sample, Peak Detect, or Hi Res mode, the digitizing oscilloscope will
acquire a waveform record with the first valid trigger event and stop.
In Envelope or Average mode, the digitizing oscilloscope will make the
specified number of acquisitions to complete the averaging or enveloping
task.
If the oscilloscope is in equivalent-time mode and you press Single
Acquisition Sequence (side), it will continue to recognize trigger events
and acquire samples until the waveform record is filled.
Hint: To quickly select Single Acquisition Sequence without displaying the
Acquire and Stop After menus, press SHIFT FORCE TRIG. Now the
RUN/STOP button operates as just described. (You still must display the
Acquire menu and then the Stop After menu to leave Single Acquisition
Sequence operation.)
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Acquisition Modes
Limit Test Condition Met (side) lets you acquire waveforms until wave-
form data exceeds the limits specified in the limit test. Then acquisition
stops. At that point, you can also specify other actions for the oscillo-
scope to take, using the selections available in the Limit Test Setup
main menu.
NOTE
In order for the digitizing oscilloscope to stop an acquisition when
limit test conditions have been met, limit testing must be turned ON,
using the Limit Test Setup main menu.
Setting up limit testing requires several more steps. You can create the
template waveform against which to compare incoming waveforms, using
the Create Limit Test Template main menu item. You can then specify
that the comparison is to be made, and the channel to compare against
the template, using the Limit Test Sources main menu item.
See Acquisition, on page 2-19.
See Limit Testing, on page 3-73.
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Autoset
The autoset function lets you quickly obtain and display a stable waveform of
usable size. Autoset automatically sets up the front panel controls based on
the characteristics of the input signal. It is much faster and easier than a
manual control-by-control setup.
Autoset makes adjustments in these areas:
Acquisition
Display
Horizontal
Trigger
Vertical
NOTE
Autoset may change vertical position in order to position the wave-
form appropriately. It always sets vertical offset to 0 V.
1. Press the Channel Selection button (such as CH 1) corresponding to your
Operation
input channel to make it active.
2. Press AUTOSET.
If you use autoset when one or more channels are displayed, the digitizing
oscilloscope selects the lowest numbered channel for horizontal scaling and
triggering. Vertically, all channels in use are individually scaled.
If you use autoset when no channels are displayed, the digitizing oscilloscope
will turn on channel one (CH 1) and scale it.
Table 3-2 on the following page lists the autoset defaults.
Autoset Defaults
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Autoset
Table 3-2: Autoset Defaults
Changed by Autoset to
Control
Selected channel
Numerically lowest of the displayed
channels
Acquire Mode
Sample
Acquire Repetitive Signal
Acquire Stop After
Display Style
On
RUN/STOP button only
Vectors
Display Intensity — Overall
(TDS 640A & TDS 620A)
If less than 50%, set to 75%
Display Format
YT
TM
FastFrame
Off
Horizontal Position
Horizontal Scale
Horizontal Time Base
Horizontal Record Length
Limit Test
Centered within the graticule window
As determined by the signal frequency
Main Only
Unchanged
Off
Trigger Position
Trigger Type
Unchanged
Edge
Trigger Source
Numerically lowest of the displayed
channels (the selected channel)
Trigger Level
Midpoint of data for the trigger source
Trigger Slope
Trigger Coupling
Trigger Holdoff
Vertical Scale
Vertical Coupling
Positive
DC
0
As determined by the signal level
DC unless AC was previously set.
AC remains unchanged.
Vertical Bandwidth
Vertical Offset
Zoom
Full
0 volts
Off
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Color (TDS 524A & TDS 644A)
The TDS 524A & TDS 644A can display information in different colors. The
Color menu lets you choose palettes of colors and decide what colors to
assign to what pieces of information.
To bring up the Color menu:
Operation
1. Press DISPLAY to show the Display menu.
2. Press Settings in the main menu until you select Color from the pop-up
menu (see Figure 3-4).
Figure 3-4: Display Menu — Setting
Color lets you alter color settings for various display components such as
waveforms and text. Display lets you adjust the style, intensity level, grati-
cule, and format features. For more information on display, see Display on
page 3-28.
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Color
Choose Palette
You can choose a palette of 13 colors from a menu of pre-set palettes.
1. Choose the starting palette by selecting Palette from the main menu.
2. Select one of the available palettes in the side menu. Choose from Nor-
mal, Bold, Hardcopy Preview or Monochrome.
3. If you are using a persistence display and wish to vary the color of each
point depending on its persistence, choose Persistence Palettes. Then
choose Temperature, Spectral, or Gray Scale from the resulting side
menu. Choose View Palette to preview your selection on the display.
Press Persistence Palette to quit preview mode. Press Clear Menu to
return to the Palette menu.
NOTE
Use at higher room temperatures or with higher intensity display
formats, such as the white fields in the Hardcopy Preview palette,
can temporarily degrade display quality.
You can select the Hardcopy Preview palette when using certain
color hardcopy formats. The default colors in the hardcopy preview
palette comprise a white background and fully saturated primary
colors which generally produce the best result.
Change Palette Colors
You can change the current palette colors. You do this by selecting a color
and varying its hue, lightness, and saturation. Hue is the wavelength of light
reflected from the surface. It varies continuously along the color spectrum as
produced by a rainbow. Lightness refers to the amount of light reflected from
the surface. It varies from black, to the nominal color, to white. Saturation is
the intensity of color. Completely desaturated color is gray. Completely satu-
rated color of any hue is that color at its most intense level.
1. Select the main menu Change Colors item (see Figure 3-5).
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Color
ScrTxt
Figure 3-5: Display Menu — Palette Colors
2. Select one of the 13 colors by pressing (repeatedly) Color in the side
menu.
3. If you want to use the factory default for this color, press the side menu
Reset to Factory Color.
4. Choose Hue from the side menu and use the general purpose knob or
keypad to select the desired hue. Values range from 0 to 359. Sample
values are: 0 = blue, 60 = magenta, 120 = red, 180 = yellow, 240 = green,
and 360 = cyan.
5. Choose Lightness from the side menu and use the general purpose
knob or keypad to select the lightness you desire. A value of 0 results in
black. A value of 50 provides the nominal color. A value of 100 results in
white.
6. Choose Saturation from the side menu and use the general purpose
knob or keypad to select the saturation you desire. A value of 100 pro-
vides a pure color. A value of 0 provides gray.
Set Math Waveform Color
To define math waveform colors:
1. Choose to define math waveform colors by selecting the main menu Map
Math item.
2. Select one of the three math waveforms by pressing Math in the side
menu.
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Color
3. If you want to assign the selected math waveform to a specific color,
press Color and cycle through the choices.
4. If you want the selected math waveform to be the same color as the
waveform it is based on, select Color Matches Contents. If the math
waveform is based on dual waveforms, the math waveform will use the
color of the first constituent waveform.
To return to the factory defaults, select Reset to Factory Color.
Set Reference Waveform Color
To define reference waveform colors:
1. Press Map Reference in the main menu (see Figure 3-6).
2. Select one of the four reference waveforms by pressing Ref in the side
menu.
3. To assign the selected reference waveform to a specific color, press
(repeatedly) Color and choose the value.
4. To make the selected reference waveform the same color as the wave-
form it is based on, select Color Matches Contents.
To return to the factory defaults, select Reset to Factory Color.
Figure 3-6: Display Menu — Map Reference Colors
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Color
Select Options
To define what color to show where a waveform crosses another waveform:
1. Press the Options main menu item.
2. Select that you wish to use a special color to mark collision zones by
toggling Collision Contrast in the side menu to ON.
Restore Colors
To restore colors to their factory default settings:
1. Press the main menu Restore Colors item (see Figure 3-7).
2. Select what you wish to restore by pressing Reset Current Palette To
Factory, Reset All Palettes To Factory or Reset All Mappings To
Factory in the side menu.
Figure 3-7: Display Menu — Restore Colors
See Display Modes, on page 3-28.
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Cursor Measurements
Use the cursors to measure the difference (either in time or voltage) between
two locations in a waveform record.
Cursors are made up of two markers that you position with the general pur-
pose knob. You move one cursor independently or both cursors in tandem,
depending on the cursor mode. As you position the cursors, readouts on the
display report measurement information.
Description
There are three cursor types: horizontal bar, vertical bar, and paired (Fig-
ure 3-8).
Horizontal bar cursors measure vertical parameters (typically volts).
Vertical bar cursors measure horizontal parameters (typically time or frequen-
cy).
Horizontal Bar Cursors
Vertical Bar Cursors
Paired Cursors
Figure 3-8: Cursor Types
Paired cursors measure both vertical parameters (typically volts) and horizon-
tal parameters (typically time) simultaneously.
Look at Figure 3-8. Note that each of the two paired cursors has a long
vertical bar paired with an X. The Xs measures vertical parameters (typically
volts); the long vertical bars measure horizontal parameters (typically time or
frequency). (See Cursor Readouts on page 3-18 for more information.)
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Cursor Measurements
NOTE
When cursors measure certain math waveforms, the measurement
may not be of time, frequency, or voltage. Cursor measurement of
those math waveforms that are not of time, frequency, or voltage is
described in Waveform Math, which begins on page 3-159.
There are two cursor modes: independent and tracking (see Figure 3-9).
Independent Mode
Tracking Mode
Only Selected Cursor
Moves
Both Cursors Move
in Tandem
Figure 3-9: Cursor Modes
In independent mode you move only one cursor at a time using the general
purpose knob. The active, or selected, cursor is a solid line. Press SELECT
to change which cursor is selected.
In tracking mode you normally move both cursors in tandem using the general
purpose knob. The two cursors remain a fixed distance (time or voltage) from
each other. Press SELECT to temporarily suspend cursor tracking. You can
then use the general purpose knob to adjust the distance of the solid cursor
relative to the dashed cursor. A second push toggles the cursors back to
tracking.
The cursor readout shows the absolute location of the selected cursor and the
difference between the selected and non-selected cursor. The readouts differ
depending on whether you are using H Bars or V Bars.
Cursor Readouts
H Bars: the value after shows the voltage difference between the
cursors. The value after @ shows the voltage of the selected cursor
relative to ground (see Figure 3-10). With the video trigger option, you
can also display the voltage in IRE units.
V Bars: the value after shows the time (or frequency) difference be-
tween the cursors. The value after @ shows the time (frequency) of the
selected cursor relative to the trigger point. With the video trigger option,
you can also display the line number.
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Cursor Measurements
In FastFrame mode, the @ shows the time position of the selected cursor
relative to the trigger point of the frame that the selected cursor is in. The
shows the time difference between the two cursors only if both cursors
are in the same frame.
Paired: the value after one shows the voltage difference between the
the two Xs; the other shows the time (or frequency) difference between
the two long vertical bars. The value after @ shows the voltage at the X
of the selected cursor relative to ground (see Figure 3-11).
In FastFrame mode, the shows the time difference between the two
cursors only if both cursors are in the same frame.
Cursor Readout (H Bars)
Non-selected Cursor
(Dashed Line)
Selected Cursor
(Solid Line)
Figure 3-10: H Bars Cursor Menu and Readouts
Paired cursors can only show voltage differences when they remain on
screen. If the paired cursors are moved off screen horizontally, Edge will
replace the voltage values in the cursor readout.
To take cursor measurements, press CURSOR to display the Cursor menu
(Figure 3-10).
Operation
Function
Select the type of cursors you want using the Function menu item:
Press CURSOR ➞ Function (main) ➞ H Bars, V Bars, Paired, or Off (side).
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Cursor Measurements
Position of Vertical Bar Cursors
(Useful for Locating Cursors
Outside the Display)
Cursor Readout (Paired)
Non-selected Cursor
(Dashed Vertical Bar)
Selected Cursor
(Solid Vertical Bar)
Figure 3-11: Paired Cursor Menu and Readouts
Mode
Select the cursor mode you want using the Mode menu item.
1. Press CURSOR ➞ Mode (main) ➞ Independent or Tracking (side):
Independent makes each cursor positionable without regard to the
position of the other cursor.
Tracking makes both cursors positionable in tandem; that is, both
cursors move in unison and maintain a fixed horizontal or vertical
distance between each other.
2. Use the general purpose knob to move the selected (active) cursor if
Independent was selected in step 1. Press SELECT to change which
cursor is active and moves. A solid line indicates the active cursor, and a
dashed line the inactive cursor.
or
Use the general purpose knob to move both cursors in tandem if Track-
ing was selected in step 1. Press SELECT to temporarily suspend cursor
tracking; then use the general purpose knob to adjust the distance of the
solid cursor relative to the dashed cursor. Press SELECT again to re-
sume tracking. A solid line indicates the adjustable cursor and a dashed
line the fixed cursor.
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Cursor Measurements
Time Units
You can choose to display vertical bar cursor results in units of time or fre-
quency. If you have Option 5 Video, you can also display the results in terms
of video line number.
Press CURSOR ➞ Time Units (main) ➞ seconds or 1/seconds (Hz) or,
with Option 5, video line number (side).
Amplitude Units
If you are measuring NTSC signals, you can choose to display vertical read-
ings in IRE units. If you are trying to do this, you should have option 05 Video
Trigger installed as it would be difficult to trigger on composite video wave-
forms without option 05.
Press CURSOR ➞ Amplitude Units (main) ➞ IRE (NTSC)
To return to normal:
Press CURSOR ➞ Amplitude Units (main) ➞ Base
Cursor Speed
You can change the cursors speed by pressing SHIFT before turning the
general purpose knob. The cursor moves faster when the SHIFT button is
lighted and the display reads Coarse Knobs in the upper right corner.
See Measurements, on page 2-30.
For More
Information
See Waveform Math, on page 3-159, for information on cursor units with
multiplied waveforms.
See Fast Fourier Transforms on page 3-38, Waveform Differentiation on
page 3-150, and Waveform Integration on page 3-154, if your oscilloscope is
equipped with Option 2F Advanced DSP Math (standard on the TDS 524A &
TDS 644A), for information on cursor units with integrated, differentiated, and
FFT waveforms.
See the TDS Family Option 05 Video Trigger Interface, if your oscilloscope is
equipped with the video trigger option, for information on cursor units with
video waveforms.
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Delayed Triggering
The TDS 600A Series oscilloscopes provide a main time base and a delayed
time base. The delayed time base, like the main time base, requires a trigger
signal and an input source dedicated to that signal. You can only use delay
with respect to the main edge trigger and certain classes of main pulse trig-
gers.
There are two different ways to delay the acquisition of waveforms: delayed
runs after main and delayed triggerable. Only delayed triggerable uses the
delayed trigger system.
Delayed runs after main looks for a main trigger, then waits a user-defined
time, and then starts acquiring (see Figure 3-12).
Wait for
Main
Trigger
Wait
User-Specified
Time
Acquire
Data
Figure 3-12: Delayed Runs After Main
Delayed triggerable looks for a main trigger and then, depending on the type
of delayed trigger selected, makes one of the three types of delayed trigger-
able mode acquisitions listed below (see Figure 3-13).
Wait for
Wait for
Main
Trigger
Wait
User-Specified
Time
Delayed
Trigger
Event
Acquire
Data
Delayed Triggerable
After Time
Wait the
User-Specified
Number of Delayed
Trigger Events
Delayed Triggerable
After Events
Wait the
Wait
User-Specified
Time
Delayed Triggerable
After Events/Time
User-Specified
Number of Delayed
Trigger Events
Figure 3-13: Delayed Triggerable
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Delayed Triggering
After Time waits the user-specified time, then waits for the next delayed
trigger event, and then acquires.
After Events waits for the specified number of delayed trigger events and
then acquires.
After Events/Time waits for the specified number of delayed trigger
events, then waits the user-specified time, and then acquires.
The digitizing oscilloscope is always acquiring samples to fill the pretrigger
part of the waveform record. When and if delay criteria are met, it takes
enough posttrigger samples to complete the delayed waveform record and
then displays it. Refer to Figure 3-14 for a more detailed look at how delayed
records are placed in time relative to the main trigger.
NOTE
When using the delayed triggerable mode, the digitizing oscillo-
scope provides a conventional edge trigger for the delayed time
base. The delayed time base will not trigger if the main trigger type
(as defined in the Main Trigger menu) is logic, if the main trigger
type is edge with its source set to auxiliary (not available on the
TDS 524A & TDS 620A), or if the main trigger type is pulse with the
runt trigger class selected.
You use the Horizontal menu to select and define either delayed runs after
main or delayed triggerable. Delayed triggerable, however, requires further
selections in the Delayed Trigger menu.
Operation
Delayed Runs After Main
1. Press HORIZONTAL MENU ➞ Time Base (main) ➞ Delayed Only
(side) ➞ Delayed Runs After Main (side). Use the general purpose knob
or the keypad to set the delay time.
If you press Intensified (side), you display an intensified zone on the
main timebase record that shows where the delayed timebase record
occurs relative to the main trigger. For Delayed Runs After Main mode,
the start of the intensified zone corresponds to the start of the delayed
timebase record. The end of the zone corresponds to the end of the
delayed record.
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Delayed Triggering
Pretrigger Record
Posttrigger Record
Delayed Runs After Main
Delayed Trigger Waveform Record
Main Trigger Point
Main
Trigger
Source
Time Delay
(From Horiz Menu)
Start Posttrigger Acquisition
Delayed Triggerable By Events
Delayed Trigger Waveform Record
Main Trigger Point
Main
Trigger
Source
Delayed
Trigger
Source
Start Posttrigger
Acquisition (Trigger on nth
Delayed Trigger Event)
Waiting for nth Event
(Where n=5)
Delayed Triggerable By Time
Delayed Trigger Waveform Record
Main Trigger Point
Main
Trigger
Source
Delayed
Trigger
Source
Time Delay
(From Delay Trig Menu)
Start Posttrigger Acquisition
(First Trigger After Delay)
Delayed Triggerable By Events/Time
Delayed Trigger Waveform Record
Main Trigger Point
Main
Trigger
Source
Delayed
Trigger
Source
Start Posttrigger Acquisition
Time Delay
(From Delay Trig Menu)
Waiting for nth Event
(Where n=4)
Figure 3-14: How the Delayed Triggers Work
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Delayed Triggering
Delayed Triggerable
You must make sure that the Main Trigger menu settings are compatible with
Delayed Triggerable.
1. Press TRIGGER MENU.
2. If Type is set to Logic, press Type (main) to change it to either Edge or
Pulse as fits your application. Logic type is incompatible with Delayed
Triggerable.
3. If Source is set to Auxiliary (not available on the TDS 524A &
TDS 620A), press Source (main). Select any source other than Auxiliary
from the side menu according to your application.
4. Press HORIZONTAL MENU ➞ Time Base (main) ➞ Delayed Only
(side) ➞ Delayed Triggerable (side).
NOTE
The Delayed Triggerable menu item is not selectable unless incom-
patible Main Trigger menu settings are eliminated. (See the steps at
the beginning of this procedure.) If such is the case, the Delayed
Triggerable menu item is dimmer than other items in the menu.
By pressing Intensified (side), you can display an intensified zone that
shows where the delayed timebase record may occur (a valid delay
trigger event must be received) relative to the main trigger on the main
time base. For Delayed Triggerable After mode, the start of the intensified
zone corresponds to the possible start point of the delayed time base
record. The end of the zone continues to the end of main time base, since
a delayed time base record may be triggered at any point after the delay
time elapses.
To learn how to define the intensity level of the normal and intensified
waveform, see Display Modes on page 3-28.
Now you need to bring up the Delayed Trigger menu so you can define
the delayed trigger event.
5. Press SHIFT DELAYED TRIG ➞ Delay by (main) ➞ Triggerable After
Time, Events, or Events/Time (side) (Figure 3-15).
6. Enter the delay time or events using the general purpose knob or the
keypad. If you selected Events/Time, use Time (side) and Events (side)
to switch between setting the time and the number of events.
Hint: You can go directly to the Delayed Trigger menu (see step 5). By
selecting one of Triggerable After Time, Events, or Events/Time, the
oscilloscope automatically switches to Delayed Triggerable in the Hori-
zontal menu. You will still need to display the Horizontal menu if you wish
to leave Delayed Triggerable.
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Delayed Triggering
The Source menu lets you select which input will be the delayed trigger
source.
7. Press Source (main) ➞ Ch1, Ch2, Ch3 (Ax1 on the TDS 524A &
TDS 620A), Ch4 (Ax2 on the TDS 524A & TDS 620A), or Auxiliary (not
available on the TDS 524A & TDS 620A) (side).
Figure 3-15: Delayed Trigger Menu
8. Press Coupling (main) ➞ DC, AC, HF Rej, LF Rej, or Noise Rej (side)
to define how the input signal will be coupled to the delayed trigger. For
descriptions of these coupling types, see Triggering on page 2-13.
9. Press Slope (main) to select the slope that the delayed trigger will occur
on. Choose between the rising edge and falling edge slopes.
When using Delayed Triggerable mode to acquire waveforms, two trigger
bars are displayed. One trigger bar indicates the level set by the main
trigger system; the other indicates the level set by the delayed trigger
system.
10. Press Level (main) ➞ Level, Set to TTL, Set to ECL, or Set to 50%
(side).
Level lets you enter the delayed trigger level using the general pur-
pose knob or the keypad.
Set to TTL fixes the trigger level at +1.4 V.
Set to ECL fixes the trigger level at –1.3 V.
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Delayed Triggering
NOTE
When you set the Vertical SCALE smaller than 200 mV, the oscillo-
scope reduces the Set to TTL or Set to ECL trigger levels below
standard TTL and ECL levels. That happens because the trigger
level range is fixed at
next smaller setting after 200 mV) the trigger range is
center. At 100 mV (the
V which
is smaller than the typical TTL (+1.4 V) or ECL (–1.3 V) level.
Set to 50% fixes the delayed trigger level to 50% of the peak-to-peak
value of the delayed trigger source signal.
See Triggering, on page 2-13.
See Triggering, on page 3-142.
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Display Modes
The digitizing oscilloscope can display waveform records in different ways.
The Display menu lets you adjust the oscilloscope display style, intensity
level, graticule, and format.
To bring up the Display menu:
Operation
1. Press DISPLAY to show the Display menu.
2. On the TDS 644A & TDS 524A, press Setting in the main menu until you
select Display from the pop-up menu.
Display lets you adjust the style, intensity level, graticule, and format features
described below. Color (TDS 644A & TDS 524A) lets you alter color settings
for various display components such as waveforms and text. For more in-
formation on color, see Color on page 3-12.
Display Style
Press DISPLAY ➞ Style (main) ➞ Vectors, Intensified Samples, Dots,
Infinite Persistence, or Variable Persistence (side) (Figure 3-16).
Figure 3-16: Display Menu — Style
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Display Modes
Vectors has the display draw vectors (lines) between the record points.
Dots display waveform record points as dots.
Intensified Samples also displays waveform record points as dots.
However, the points actually sampled are displayed in the Zone color
(TDS 644A & TDS 524A) or intensified relative to the interpolated points.
In addition to choosing Intensified Samples in the side menu, the oscilloscope
must be interpolating (equivalent time must be off) or Zoom must be on with
its horizontal expansion greater that 1X. See interpolation on page 2-21; see
Zoom beginning on page 3-162.
Variable Persistence lets the record points accumulate on screen over
many acquisitions and remain displayed only for a specific time interval.
In that mode, the display behaves like that of an analog oscilloscope. You
enter the time for that option with the keypad or the general purpose
knob. On color instruments, record points are also displayed with colors
that vary depending on the points persistence. See Choose Palette on
page 3-13.
Infinite Persistence lets the record points accumulate until you change
some control (such as scale factor) causing the display to be erased.
Intensity
Intensity lets you set text/graticule and waveform intensity (brightness) levels.
To set the intensity:
Press DISPLAY ➞ Intensity (main) ➞ Overall (TDS 640A & TDS 620A),
Text/Grat, Waveform, or Contrast (TDS 640A & TDS 620A) (side). Enter the
intensity percentage values with the keypad or the general purpose knob.
All intensity adjustments operate over a range from 20% (close to fully off) to
100% (fully bright).
Contrast (TDS 640A & TDS 620A) operates over a range from 100% (no
contrast) to 250% (intensified portion at full brightness).
NOTE
The Intensified setting for Timebase in the horizontal menu causes
a zone on the waveform to be displayed in the Zone color
(TDS 644A & TDS 524A) or intensified relative to the rest of the
waveform. If the contrast is set to 100%, you won’t be able to
distinguish the intensified portion from the rest of the waveform
because both are the same brightness.
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Display Modes
Display Readout
Readout options control whether the trigger indicator, trigger level bar, and
current date and time appear on the display. The options also control what
style trigger level bar, long or short, is displayed.
1. Press DISPLAY ➞ Readout (main).
2. Toggle Display ‘T’ @ Trigger Point (side) to select whether or not to
display ‘T’ indicating the trigger point. You can select ON or OFF. (The
trigger point indicates the position of the trigger in the waveform record.)
3. Press Trigger Bar Style (side) to select either the short or the long
trigger bar or to turn the trigger bar off. (See Figure 3-17. Note that both
styles are shown for illustrating purposes, but you can only display one
style at a time.)
The trigger bar is only displayed if the trigger source is an active, dis-
played waveform. Also, two trigger bars are displayed when delay trigger-
able acquisitions are displayed — one for the main and one for the
delayed timebase. The trigger bar is a visual indicator of the trigger level.
Sometimes, especially when using the hardcopy feature, you may wish to
display the current date and time on screen. For more information about
displaying and setting date and time, see Date/Time Stamping Your
Hardcopy on page 3-62.)
4. Press Display Date/Time (side) to turn it on or off. Push Clear Menu to
see the current date and time.
Trigger Point Indicator
Trigger Bar—Long Style
–or–
Trigger Bar—Short
Style
Figure 3-17: Trigger Point and Level Indicators
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Display Modes
Filter Type
The display filter types are sin(x)/x interpolation and linear interpolation. For
more information see the Concepts section, page 2-21.
Press DISPLAY ➞ Filter (main) ➞ Sin(x)/x Interpolation or Linear Interpo-
lation (side).
NOTE
When the horizontal scale is set to rates faster than 50 ns/div, or
when using the ZOOM feature to expand waveforms horizontally,
interpolation occurs. (The filter type, linear or sin(x)/(x), depends on
which is set in the Display menu.) Otherwise, interpolation is not
needed. See Sampling and Digitizing on page 2-19 for a discussion
of sampling including interpolation.
Graticule Type
To change the graticule:
Press DISPLAY ➞ Graticule (main) ➞ Full, Grid, Cross Hair, Frame,
NTSC or PAL (side).
Full provides a grid, cross hairs and a frame.
Grid displays a frame and a grid.
Cross Hair provides cross hairs, and a frame.
Frame displays just a frame.
NTSC provides a grid useful for measuring NTSC-class waveforms.
PAL provides a grid useful for measuring PAL-class waveforms.
NOTE
Selecting either NTSC or PAL graticules automatically changes the
vertical scale, position settings, coupling, and sets to zero any
vertical offset of any channel displayed. These settings are not
restored after switching to other graticule types. Therefore, you
might wish to recall the factory setup or other stored setup after
selecting a different graticule.
Format
There are two kinds of format: YT and XY.
YT is the conventional oscilloscope display format. It shows a signal voltage
(the vertical axis) as it varies over time (the horizontal axis).
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Display Modes
XY format compares the voltage levels of two waveform records point by
point. That is, the digitizing oscilloscope displays a graph of the voltage of one
waveform record against the voltage of another waveform record. This mode
is particularly useful for studying phase relationships.
To set the display axis format:
Press DISPLAY ➞ Format (main) ➞ XY or YT (side).
When you choose the XY mode, the input you have selected is assigned to
the X-axis, and the digitizing oscilloscope automatically chooses the Y-axis
input (see Table 3-3).
Table 3-3: XY Format Pairs
X-Axis Channel
(User Selectable)
Y-Axis Channel
(Fixed)
Ch 1
Ch 2
Ch 3 (TDS 644A & TDS 640A)
(Aux 1 on the TDS 524A &
TDS 620A)
Ch 4 (TDS 644A & TDS 640A)
(Aux 2 on the TDS 524A &
TDS 620A)
Ref 1
Ref 3
Ref 2
Ref 4
For example, if you press the CH 1 button, the digitizing oscilloscope will
display a graph of the channel 1 voltage levels on the X-axis against the
channel 2 voltage levels on the Y-axis. That will occur whether or not you are
displaying the channel 2 waveform in YT format. If you later press the WAVE-
FORM OFF button for either channel 1 or 2, the digitizing oscilloscope will
delete the XY graph of channel 1 versus channel 2.
Since selecting YT or XY affects only the display, the horizontal and vertical
scale and position knobs and menus control the same parameters regardless
of the mode selected. Specifically, in XY mode, the horizontal scale will
continue to control the time base and the horizontal position will continue to
control which portion of the waveforms are displayed.
XY format is a dot-only display, although it can have persistence. The Vector
style selection has no effect when you select XY format.
You cannot display Math waveforms in XY format. They will disappear from
the display when you select XY.
NOTE
Use at higher room temperatures or with higher intensity display
formats, such as the white fields in the Hardcopy palette, can
temporarily degrade display quality.
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Display Modes
See Acquisition, on page 2-19.
See Color, on page 3-12.
For More
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See Measurements, on page 2-30.
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Edge Triggering
An edge trigger event occurs when the trigger source passes through a
specified voltage level in a specified direction (the trigger slope). You will likely
use edge triggering for most of your measurements.
You can select the edge source, coupling, slope, level, and mode (auto or
normal).
The Trigger readout shows some key trigger parameters (Figure 3-18).
Edge Trigger
Readouts
Main Time Base Time/Div
Main Time Base
Main Trigger
Source = Ch 1
Main Trigger
Slope = Rising Edge
Main Trigger
Level
Figure 3-18: Edge Trigger Readouts
The Edge Trigger menu lets you select the source, coupling, slope, trigger
level, mode, and holdoff.
Operation
To bring up the Edge Trigger menu:
Press TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) (see Figure 3-19).
Source
To select which source you want for the trigger:
Press TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞
Source (main) ➞ Ch1, Ch2, Ch3 (Ax1 on the TDS 620A & TDS 524A), Ch4
(Ax2 on the TDS 620A & TDS 524A), AC Line, or Auxiliary (TDS 640A &
TDS 644A) (side).
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Edge Triggering
Figure 3-19: Main Trigger Menu — Edge Type
Coupling
To select the coupling you want:
Press TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞ Cou-
pling (main) ➞ DC, AC, HF Rej, LF Rej, or Noise Rej (side).
DC passes all of the input signal. In other words, it passes both AC and
DC components to the trigger circuit.
AC passes only the alternating components of an input signal (above
30 Hz). It removes the DC component from the trigger signal.
HF Rej removes the high frequency portion of the triggering signal. That
allows only the low frequency components to pass on to the triggering
system to start an acquisition. High frequency rejection attenuates signals
above 30 kHz.
LF Rej does the opposite of high frequency rejection. Low frequency
rejection attenuates signals below 80 kHz.
Noise Rej provides lower sensitivity. Noise Rej requires additional signal
amplitude for stable triggering, reducing the chance of falsely triggering
on noise.
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Edge Triggering
Slope
To select the slope that the edge trigger will occur on:
1. Press the TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞
Slope (main).
2. Alternatives for slope are the rising and falling edges.
Level
Press the TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞
Level (main) ➞ Level, Set to TTL, Set to ECL, or Set to 50% (side).
Level lets you enter the trigger level using the general purpose knob or
the keypad.
Set to TTL fixes the trigger level at +1.4 V.
Set to ECL fixes the trigger level at –1.3 V.
NOTE
When you set the volts/div smaller than 200 mV, the oscilloscope
reduces the Set to TTL or Set to ECL trigger levels below standard
TTL and ECL levels. That happens because the trigger level range
is fixed at
center. At 100 mV (the next small-
V, which is smaller
er setting after 200 mV) the trigger range is
than the typical TTL (+1.4 V) or ECL (–1.3 V) level.
Set to 50% fixes the trigger level to approximately 50% of the peak-to-
peak value of the trigger source signal.
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Edge Triggering
Mode & Holdoff
You can change the holdoff time and select the trigger mode using this menu
item. See Triggering on page 2-13 for more details.
1. Press the TRIGGER MENU ➞ Mode & Holdoff (main) ➞ Auto or Nor-
mal (side).
In Auto mode the oscilloscope acquires a waveform after a specific
time has elapsed even if a trigger does not occur. The amount of time
the oscilloscope waits depends on the time base setting.
In Normal mode the oscilloscope acquires a waveform only if there is
a valid trigger.
2. To change the holdoff time, press Holdoff (side). Enter the value in %
using the general purpose knob or the keypad.
If you want to enter a large number using the general purpose knob, press the
SHIFT button before turning the knob. When the light above the SHIFT button
is on and the display says Coarse Knobs in the upper right corner, the
general purpose knob speeds up significantly.
You can set holdoff from 0% (minimum holdoff available) to 100% (maximum
available). See Holdoff, Variable, Main Trigger in the TDS 520A, 524A, 540A,
& 544A Performance Verification Manual, Section 2 on Specifications, Typical
Characteristics for typical minimum and maximum values.
Holdoff is automatically reset to 0% when you change the main time base
time/division setting. However, it is not reset if you change the delayed time
base time/division (that is, when the time base setting in the Horizontal menu
is Intensified or Delayed Only).
See Triggering, on page 2-13.
See Triggering, on page 3-142.
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Fast Fourier Transforms
Advanced DSP Math (optional on TDS 620A & TDS 640A), provides the Fast
Fourier Transform (FFT). The FFT allows you to transform a waveform from a
display of its amplitude against time to one that plots the amplitudes of the
various discrete frequencies the waveform contains. Further, you can also
display the phase shifts of those frequencies. Use FFT math waveforms in
the following applications:
Testing impulse response of filters and systems
Measuring harmonic content and distortion in systems
Characterizing the frequency content of DC power supplies
Analyzing vibration
Analyzing harmonics in 50 and 60 cycle lines
Identifying noise sources in digital logic circuits
The FFT computes and displays the frequency content of a waveform you
acquire as an FFT math waveform. This frequency domain waveform is
based on the following equation:
Description
Where:
x(n) is a point in the time domain record data array
X(k) is a point in the frequency domain record data array
n is the index to the time domain data array
k is the index to the frequency domain data array
N is the FFT length
j is the square root of −1
The resulting waveform is a display of the magnitude or phase angle of the
various frequencies the waveform contains with respect to those frequencies.
For example, Figure 3-20 shows the non-transformed impulse response of a
system in channel 2 at the top of the screen. The FFT-transformed magnitude
and phase appear in the two math waveforms below the impulse. The hori-
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Fast Fourier Transforms
zontal scale for FFT math waveforms is always expressed in frequency per
division with the beginning (left-most point) of the waveform representing zero
frequency (DC).
The FFT waveform is based on digital signal processing (DSP) of data, which
allows more versatility in measuring the frequency content of waveforms. For
example, DSP allows the oscilloscope to compute FFTs of source waveforms
that must be acquired based on a single trigger, making it useful for measur-
ing the frequency content of single events.
Normal Waveform of
an Impulse Response
FFT Waveform of the
Magnitude Response
FFT Waveform of the
Phase Response
Figure 3-20: System Response to an Impulse
To obtain an FFT of your waveform:
Operation
1. Connect the waveform to the desired channel input and select that chan-
nel.
2. Adjust the vertical and horizontal scales and trigger the display (or press
AUTOSET).
The topic Offset, Position, and Scale, on page 3-46, provides in depth
information about optimizing your setup for FFT displays.
3. Press MORE to access the menu for turning on math waveforms.
4. Select a math waveform. Your choices are Math1, Math2, and
Math3 (main).
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Fast Fourier Transforms
Figure 3-21: Define FFT Waveform Menu
5. If the selected math waveform is not FFT, press Change Math Definition
(side) ➞ FFT (main). See Figure 3-21.
6. Press Set FFT Source to (side) repeatedly until the channel source
selected in step 1 appears in the menu label.
7. Press Set FFT Vert Scale to (side) repeatedly to choose from the follow-
ing vertical scale types:
dBV RMS — Magnitude is displayed using log scale, expressed in dB
relative to 1 V
where 0 dB =1 V
.
RMS
RMS
Linear RMS — Magnitude is displayed using voltage as the scale.
Phase (deg) — Phase is displayed using degrees as the scale,
where degrees wrap from –180 to +180 .
Phase (rad) — Phase is displayed using radians as the scale, where
radians wrap from – to + .
The topic Considerations for Phase Displays, on page 3-49, provides in
depth information on setup for phase displays.
8. Press Set FFT Window to (side) repeatedly to choose from the following
window types:
Rectangular — Best type for resolving frequencies that are very
close to the same value but worst for accurately measuring the
amplitude of those frequencies. Best type for measuring the frequen-
cy spectrum of non-repetitive signals and measuring frequency
components near DC.
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Fast Fourier Transforms
Hamming — Very good window for resolving frequencies that are
very close to the same value with somewhat improved amplitude
accuracy over the rectangular window.
Hanning — Very good window for measuring amplitude accuracy
but degraded for resolving frequencies.
Blackman-Harris — Best window for measuring the amplitude of
frequencies but worst at resolving frequencies.
The topic Selecting the Window, on page 3-51, provides in depth informa-
tion on choosing the right window for your application.
9. If you did not select Phase (deg) or Phase (rad) in step 7, skip to
step 12. Phase suppression is only used to reduce noise in phase FFTs.
10. If you need to reduce the effect of noise in your phase FFT, press Sup-
press phase at amplitudes < (side).
11. Use the general purpose knob (or the keypad if your oscilloscope is so
equipped) to adjust the phase suppression level. FFT magnitudes below
this level will have their phase set to zero.
The topic Adjust Phase Suppression, on page 3-50, provides additional
information on phase suppression.
12. Press OK Create Math Wfm (side) to display the FFT of the waveform
you input in step 1 (see Figure 3-22).
Figure 3-22: FFT Math Waveform in Math1
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Fast Fourier Transforms
Cursor Measurements of an FFT
Once you have displayed an FFT math waveform, use cursors to measure its
frequency amplitude or phase angle.
1. Be sure MORE is selected in the channel selection buttons and that the
FFT math waveform is selected in the More main menu.
2. Press CURSOR ➞ Mode (main) ➞ Independent (side) ➞ Func-
tion (main) ➞ H Bars (side).
3. Use the general purpose knob to align the selected cursor (solid line) to
the top (or to any amplitude on the waveform you choose).
4. Press SELECT to select the other cursor. Use the general purpose knob
to align the selected cursor to the bottom (or to any amplitude on the
waveform you choose).
5. Read the amplitude between the two cursors from the : readout. Read
the amplitude of the selected cursor relative to either 1 V
(0 dB),
RMS
ground (0 volts), or the zero phase level (0 degrees or 0 radians) from the
@: readout. (The waveform reference indicator at the left side of the
graticule indicates the level where phase is zero for phase FFTs.)
Figure 3-23 shows the cursor measurement of a frequency magnitude on
an FFT. The @: readout reads 0 dB because it is aligned with the 1 V
RMS
level. The : readout reads 24.4 dB indicating the magnitude of the
frequency it is measuring is –24.4 dB relative to 1 V
waveform is turned off in the display.
. The source
RMS
The cursor units will be in dB or volts for FFTs measuring magnitude and
in degrees or radians for those FFTs measuring phase. The cursor unit
depends on the selection made for Set FFT Vert Scale to (side). See
step 7 on page 3-40 for more information.
6. Press V Bars (side). Use the general purpose knob to align one of the
two vertical cursors to a point of interest along the horizontal axis of the
waveform.
7. Press SELECT to select the alternate cursor.
8. Align the selected cursor to another point of interest on the math wave-
form.
9. Read the frequency difference between the cursors from the : readout.
Read the frequency of the selected cursor relative to the zero frequency
point from the @: readout.
The cursor units will always be in Hz, regardless of the setting in the
Time Units side menu. The first point of the FFT record is the zero
frequency point for the @: readout.
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Fast Fourier Transforms
Figure 3-23: Cursor Measurement of an FFT Waveform
10. Press Function (main) ➞ Paired (side).
11. Use the technique just outlined to place the vertical bar of each paired
cursor to the points along the horizontal axis you are interested in.
12. Read the amplitude between the X of the two paired cursors from the
top-most : readout. Read the amplitude of the short horizontal bar of the
selected (solid) cursor relative to either 1 V
(0 dB), ground (0 volts), or
RMS
zero phase level (0 degrees or 0 radians) from the @: readout. Read the
frequency between the long horizontal bars of both paired cursors from
the bottom : readout.
Automated Measurements of an FFT
You can also use automated measurements to measure FFT math wave-
forms. Use the same procedure as is found under Waveform Differentiation
on page 3-151.
There are several characteristics of FFTs that affect how they are displayed
and should be interpreted. Read the following topics to learn how to optimize
the oscilloscope setup for good display of your FFT waveforms.
Considerations for
Using FFTs
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Fast Fourier Transforms
The FFT Frequency Domain Record
The following topics discuss the relation of the source waveform to the record
length, frequency resolution, and frequency range of the FFT frequency
domain record. (The FFT frequency domain waveform is the FFT math
waveform that you display.)
FFTs May Not Use All of the Waveform Record — The FFT math
waveform is a display of the magnitude or phase data from the FFT frequency
domain record. This frequency domain record is derived from the FFT time
domain record, which is derived from the waveform record. All three records
are described below.
Waveform Record — the complete waveform record acquired from an input
channel and displayed from the same channel or a reference memory. The
length of this time domain record is user-specified from the Horizontal menu.
The waveform record is not a DSP Math waveform.
FFT Time Domain Record — that part of the waveform record that is input to
the FFT. This time domain record waveform becomes the FFT math wave-
form after it is transformed. Its record length depends on the length of the
waveform record defined above.
FFT Frequency Domain Record — the FFT math waveform after digital signal
processing converts data from the FFT time domain record into a frequency
domain record.
Figure 3-24 compares the waveform record to the FFT time domain record.
Note the following relationships:
For waveform records ≤10 K points in length, the FFT uses all of the
waveform record as input.
For waveform records >10 K points, the first 10 K points of the waveform
record becomes the FFT time domain record.
Each FFT time domain record starts at the beginning of the acquired
waveform record.
The zero phase reference point for a phase FFT math waveform is in the
middle of the FFT time domain record regardless of the waveform record
length.
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Fast Fourier Transforms
FFT Time Domain Record =
Waveform Record
Waveform Record ≤ 10 K
Zero Phase
Reference
FFT Time Domain Record = 10k
Waveform Record > 10 K
Zero Phase
Reference
Figure 3-24: Waveform Record vs. FFT Time Domain Record
FFTs Transform Time Records to Frequency Records — The FFT
time domain record just described is input for the FFT. Figure 3-25 shows the
transformation of that time domain data record into an FFT frequency domain
record. The resulting frequency domain record is one half the length of the
FFT input because the FFT computes both positive and negative frequencies.
Since the negative values mirror the positive values, only the positive values
are displayed.
FFT Time Domain Record
FFT
FFT Frequency Domain Record
Figure 3-25: FFT Time Domain Record vs. FFT Frequency Domain
Record
FFT Frequency Range and Resolution — When you turn on an FFT
waveform, the oscilloscope displays either the magnitude or phase angle of
the FFT frequency domain record. The resolution between the discrete fre-
quencies displayed in this waveform is determined by the following equation:
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Fast Fourier Transforms
Where:
form
F is the frequency resolution.
Sample Rate is the sample rate of the source waveform.
FFT Length is the length of the FFT Time Domain wave-
record.
The sample rate also determines the range these frequencies span; they
span from 0 to
the
sample rate is often referred to as the Nyquist frequency or point.) For exam-
ple, a sample rate of 20 Megasamples per second would yield an FFT with a
range of 0 to 10 MHz. The sample rates available for acquiring data records
vary over a range the limits of which depend on your oscilloscope model. TDS
oscilloscopes display the sample rate in the acquisition readout at the top of
the oscilloscope screen.
Offset, Position, and Scale
The following topics contain information to help you display your FFT proper-
ly.
Adjust for a Non-Clipped Display — To properly display your FFT wave-
form, scale the source waveform so it is not clipped.
You should scale and position the source waveform so it is contained on
screen. (Off screen waveforms may be clipped, resulting in errors in the
FFT waveform).
Alternately, to get maximum vertical resolution, you can display source
waveforms with amplitudes up to two divisions greater than that of the
screen. If you do, turn on Pk-Pk in the measurement menu and monitor
the source waveform for clipping.
Use vertical position and vertical offset to position your source waveform.
As long as the source waveform is not clipped, its vertical position and
vertical offset will not affect your FFT waveform except at DC. (DC
correction is discussed below.)
Adjust Offset and Position to Zero for DC Correction — Normally, the
output of a standard FFT computation yields a DC value that is twice as large
as it should be with respect to the other frequencies. Also, the selection of
window type introduces errors in the DC value of an FFT.
The displayed output of the FFT on TDS oscilloscopes is corrected for these
errors to show the true value for the DC component of the input signal. The
Position and Offset must be set to zero for the source waveform in the
Vertical menu. When measuring the amplitude at DC, remember that 1 VDC
equals 1 V
and the display is in dB.
RMS
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Fast Fourier Transforms
Record Length
Most often, you will want to use a short record length because more of the
FFT waveform can be seen on screen and long record lengths can slow
oscilloscope response. However, long record lengths lower the noise relative
to the signal and increase the frequency resolution for the FFT. More impor-
tant, they might be needed to capture the waveform feature you want to
include in the FFT.
To speed up oscilloscope response when using long record lengths, you can
save your source waveform in a reference memory and perform an FFT on
the saved waveform. That way the DSP will compute the FFT based on
saved, static data and will only update if you save a new waveform.
Acquisition Mode
Selecting the right acquisition mode can produce less noisy FFTs.
Set up in Sample or Normal Mode — Use sample mode until you have set
up and turned on your FFT. Sample mode can acquire repetitive and nonre-
petitive waveforms and does not affect the frequency response of the source
waveform.
Hi Res and Average Reduce Noise — After the FFT is set up and dis-
played, it might be useful to turn on Hi Res mode, on TDS models so
equipped, to reduce the effect of noise in the signal. Hi Res operates on both
repetitive and nonrepetitive waveforms; however, it does affect the frequency
response of the source waveform.
If the pulse is repetitive, Average mode may be used to reduce noise in the
signal at a cost of slower display response. Average operates on repetitive
waveforms only, and averaging does affect the frequency response of the
source waveform.
Peak Detect (on TDS models so equipped) and Envelope mode can add
significant distortion to the FFT results and are not recommended for use with
FFTs.
Zoom and Interpolation
Once you have your waveform displayed optimally, you may magnify (or
reduce) it vertically and horizontally to inspect any feature you desire. Just be
sure the FFT waveform is the selected waveform. (Press MORE, then select
the FFT waveform in the More main menu. Then use the Vertical and Hori-
zontal SCALE knobs to adjust the math waveform size.)
If you wish to see the zoom factor (2X, 5X, etc.) you need to turn Zoom on:
press ZOOM ➞ On (side). The vertical and horizontal zoom factors appear
on screen.
Whether Zoom is on or off, you can press Reset Zoom Factors (side) to
return the zoomed FFT waveform to no magnification.
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Zoom always uses either sin(x)/x or linear interpolation when expanding
displayed waveforms. To select the interpolation method: press DISPLAY ➞
Setting (main) ➞ Display (pop-up) ➞ Filter (main) ➞ Sin(x)/x or Linear
(side), or if your oscilloscope does not have color, press DISPLAY ➞ Fil-
ter (main) ➞ Sin(x)/x or Linear (side)
If the source waveform record length is 500 points, the FFT will use 2X Zoom
to increase the 250 point FFT frequency domain record to 500 points. There-
fore, FFT math waveforms of 500 point waveforms are always zoomed 2X or
more with interpolation. Waveforms with other record lengths can be zoomed
or not and can have minimum Zooms of 1X or less.
Sin(x)/x interpolation may distort the magnitude and phase displays of the
FFT depending on which window was used. You can easily check the effects
of the interpolation by switching between sin(x)/x and linear interpolation and
observing the difference in measurement results on the display. If significant
differences occur, use linear interpolation.
Undersampling (Aliasing)
Aliasing occurs when the oscilloscope acquires a source waveform with
frequency components outside of the frequency range for the current sample
rate. In the FFT waveform, the actual higher frequency components are
undersampled, and therefore, they appear as lower frequency aliases that
“fold back” around the Nyquist point (see Figure 3-26).
The greatest frequency that can be input into any sampler without aliasing is
frequency. Since source waveforms often have a fundamental
frequency that does not alias but have harmonic frequencies that do, you
should have methods for recognizing and dealing with aliases:
Be aware that a source waveform with fast edge transition times creates
many high frequency harmonics. These harmonics typically decrease in
amplitude as their frequency increases.
Sample the source signal at rates that are at least 2X that of the highest
frequency component having significant amplitude.
Filter the input to bandwidth limit it to frequencies below that of the Ny-
quist frequency.
Recognize and ignore the aliased frequencies.
If you think you have aliased frequencies in your FFT, select the source
channel and adjust the horizontal scale to increase the sample rate. Since
you increase the Nyquist frequency as you increase the sample rate, the alias
signals should appear at their proper frequency.
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Fast Fourier Transforms
Nyquist Frequency
Point
Frequency
AliasedFrequencies
Actual Frequencies
Figure 3-26: How Aliased Frequencies Appear in an FFT
Considerations for Phase Displays
When you set up an FFT math waveform to display the phase angle of the
frequencies contained in a waveform, you should take into account the refer-
ence point the phase is measured against. You may also need to use phase
suppression to reduce noise in your FFTs.
Establish a Zero Phase Reference Point — The phase of each fre-
quency is measured with respect to the zero phase reference point. The zero
reference point is the point at the center of the FFT math waveform but
corresponds to various points on the source (time domain) record. (See
Figure 3-24 on page 3-45.)
To measure the phase relative to most source waveforms, you need only to
center the positive peak around the zero phase point. (For instance, center
the positive half cycle for a sine or square wave around the zero phase point.)
Use the following method:
First be sure the FFT math waveform is selected in the More menu, then
set horizontal position to 50% in the Horizontal menu. This positions the
zero phase reference point to the horizontal center of the screen.
In the Horizontal menu, vary the trigger position to center the positive
peak of the source waveform at the horizontal center of screen. Alternate-
ly, you can adjust the trigger level (knob) to bring the positive peak to
center screen if the phase reference waveform has slow enough edges.
When impulse testing and measuring phase, align the impulse input into the
system to the zero reference point of the FFT time domain waveform:
Set the trigger position to 50% and horizontal position to 50% for all
record lengths less than 15 K. (Your model oscilloscope may not have
record lengths of 15 K or longer — consult your User manual.)
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For records with a 15 K length, set the trigger position to 33%. Use the
horizontal position knob to move the trigger T on screen to the center
horizontal graticule line.
For records with 30 K, 50 K, or 60 K lengths (not all lengths are available
for all TDS models — consult your User manual), set the trigger position
to 16.6%,10%, or 8.3%, respectively. Use the horizontal position knob to
move the trigger T on screen and to the center horizontal graticule line.
Trigger on the input impulse.
Adjust Phase Suppression — Your source waveform record may have a
noise component with phase angles that randomly vary from −pi to pi. This
noise could make the phase display unusable. In such a case, use phase
suppression to control the noise.
You specify the phase suppression level in dB with respect to 1 V
. If the
RMS
magnitude of the frequency is greater than this threshold, then its phase
angle will be displayed. However, if it is less than this threshold, then the
phase angle will be set to zero and be displayed as zero degrees or radians.
(The waveform reference indicator at the left side of the graticule indicates
the level where phase is zero for phase FFTs.)
It is easier to determine the level of phase suppression you need if you first
create a frequency FFT math waveform of the source and then create a
phase FFT waveform of the same source. Do the following steps to use a
cursor measurement to determine the suppression level:
1. Do steps 1 through 7 of Operation that begins on page 3-39. Select dBV
RMS (side) for the Set FFT Vert Scale to (side).
2. Press CURSOR ➞ Mode (main) ➞ Independent (side) ➞ Func-
tion (main) ➞ H Bars (side). Use the general purpose knob to align the
selected cursor to a level that places the tops of the magnitudes of fre-
quencies of interest above the cursor but places other magnitudes com-
pletely below the cursor.
3. Read the level in dB from the @: readout. Note the level for use in step 5.
4. Press MORE (main) ➞ Change Waveform Definition menu (side).
Press Set FFT Vert Scale to (side) repeatedly to choose either Phase
(rad) or Phase (deg).
5. Press Suppress Phase at Amplitudes (side). Use the general purpose
knob (or keypad if your oscilloscope is so equipped) to set phase sup-
pression to the value obtained using the H Bar cursor. Do not change the
window selection or you will invalidate the results obtained using the
cursor.
FFT Windows
To learn how to optimize your display of FFT data, read about how the FFT
windows data before computing the FFT math waveform. Understanding FFT
windowing can help you get more useful displays.
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Fast Fourier Transforms
Windowing Process — The oscilloscope multiplies the FFT time domain
record by one of four FFT windows before it inputs the record to the FFT
function. Figure 3-27 shows how the time domain record is processed.
The FFT windowing acts like a bandpass filter between the FFT time domain
record and the FFT frequency domain record. The shape of the window
controls the ability of the FFT to resolve (separate) the frequencies and to
accurately measure the amplitude of those frequencies.
Selecting a Window — You can select your window to provide better
frequency resolution at the expense of better amplitude measurement accura-
cy in your FFT, better amplitude accuracy over frequency resolution, or to
provide a compromise between both. You can choose from these four win-
dows: Rectangular, Hamming, Hanning, and Blackman-Harris.
In step 8 (page 3-40) in Displaying an FFT, the four windows are listed in
order according to their ability to resolve frequencies versus their ability to
accurately measure the amplitude of those frequencies. The list indicates that
the ability of a given window to resolve a frequency is inversely proportional to
its ability to accurately measure the amplitude of that frequency. In general,
then, choose a window that can just resolve between the frequencies you
want to measure. That way, you will have the best amplitude accuracy and
leakage elimination while still separating the frequencies.
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Fast Fourier Transforms
FFT Time Domain Record
Xs
FFT Window
FFT Time Domain Record
After Windowing
FFT
FFT Frequency Domain Record
Figure 3-27: Windowing the FFT Time Domain Record
You can often determine the best window empirically by first using the window
with the most frequency resolution (rectangular), then proceeding toward that
window with the least (Blackman-Harris) until the frequencies merge. Use the
window just before the window that lets the frequencies merge for best com-
promise between resolution and amplitude accuracy.
NOTE
If the Hanning window merges the frequencies, try the Hamming
window before settling on the rectangular window. Depending on the
distance of the frequencies you are trying to measure from the
fundamental, the Hamming window sometimes resolves frequencies
better than the Hanning.
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Fast Fourier Transforms
Window Characteristics — When evaluating a window for use, you may
want to examine how it modifies the FFT time domain data. Figure 3-28
shows each window, its bandpass characteristic, bandwidth, and highest side
lobe. Consider the following characteristics:
The narrower the central lobe for a given window, the better it can resolve
a frequency.
The lower the lobes on the side of each central lobe are, the better the
amplitude accuracy of the frequency measured in the FFT using that
window.
Narrow lobes increase frequency resolution because they are more
selective. Lower side lobe amplitudes increases accuracy because they
reduce leakage.
Leakage results when the FFT time domain waveform delivered to the
FFT function contains a non-integer number of waveform cycles. Since
there are fractions of cycles in such records, there are discontinuities at
the ends of the record. These discontinuities cause energy from each
discrete frequency to “leak” over on to adjacent frequencies. The result is
amplitude error when measuring those frequencies.
The rectangular window does not modify the waveform record points; it
generally gives the best frequency resolution because it results in the most
narrow lobe width in the FFT output record. If the time domain records you
measured always had an integer number of cycles, you would only need this
window.
Hamming, Hanning, and Blackman-Harris are all somewhat bell-shaped
widows that taper the waveform record at the record ends. The Hanning and
Blackman/Harris windows taper the data at the end of the record to zero;
therefore, they are generally better choices to eliminate leakage.
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FFT Window Type
Bandpass Filter
-3 dB Bandwidth
Highest Side Lobe
0.89
-13 dB
Rectangular Window
1.28
1.28
1.28
–43 dB
–32 dB
–94 dB
Hamming Window
Hanning Window
Blackman-Harris
Window
Figure 3-28: FFT Windows and Bandpass Characteristics
Care should be taken when using bell shaped widows to be sure that the
most interesting parts of the signal in the time domain record are positioned in
the center region of the window so that the tapering does not cause severe
errors.
See Waveform Differentiation, on page 3-150.
See Waveform Integration, on page 3-154.
See Waveform Math, on page 3-159.
For More
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File System (Optional on TDS 620A &
TDS 640A)
The File Utilities menu, which comes with the Hardcopy, Save Setup, and
Save Waveforms menus, gives you a variety of features for managing the
floppy disk.
The File Utilities menu lets you delete, rename, copy, print files, create a new
directory, operate the confirm delete and overwrite lock, and format disks.
Operation
To bring up the File Utilities menu:
1. Press the SETUP button to bring up the Save/Recall Setup menu, or
press the WAVEFORM button to bring up the Save/Recall Waveform
menu, or press the Shift HARDCOPY button to bring up the Hardcopy
menu.
2. Press File Utilities in the main menu to bring up the File Utilities side
menu. (see Figure 3-29).
Figure 3-29: File Utilities
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File System
NOTE
The amount of free space on the disk is shown in the upper right
corner of the display. The digitizing oscilloscope shows the amount
in K bytes. To convert the amount to bytes, you simply multiply the
K bytes amount times 1024. Thus, the 711 kB shown in Figure 3-29
= 711 Kbytes * 1024 bytes/K = 728,064 bytes.
Delete
To delete a file or directory, turn the general purpose knob until it scrolls the
cursor over the name of the file or directory to delete. Then, press the side
menu Delete button.
To delete all files in the file list, set the cursor to the *.* selection.
The digitizing oscilloscope deletes directories recursively. That means it
deletes both the directories and all their contents.
Rename
To rename a file or directory, turn the general purpose knob until it scrolls the
cursor over the name of the file or directory to delete. For example, to rename
the target file whose default name is TEK????? set the cursor over its name.
Then, press the side menu Rename button.
The labelling menu should appear. Turn the general purpose knob or use the
main-menu arrow keys to select each letter. Press Enter Char from the main
menu to enter each letter. When you have entered the name, press the side
menu OK Accept item (See Figure 3-30).
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File System
Figure 3-30: File System — Labelling Menu
Copy
To copy a file or directory, turn the general purpose knob until it scrolls the
cursor over the name of the file to copy. Then, press the side menu Copy
button. The file menu will reappear with the names of directories to copy to.
Select a directory and press the side-menu button labelled Copy <name> to
Selected Directory.
To copy all files, select the *.* entry.
The digitizing oscilloscope copies all directories recursively. That means it
copies both the directories and all their contents.
Print
To print a file, turn the general purpose knob until it scrolls the cursor over the
name of the file to print. Then, press the side-menu Print button.
The Print-To side menu should appear. Select the port to print to from GPIB,
RS-232, or Centronics. (See Figure 3-30) Then the digitizing oscilloscope
will send the file in its raw form out the port. The device (printer) receiving the
file must be capable or printing the particular file format.
Create Directory
To create a new directory, press the side menu Create Directory button.
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The labelling menu should appear. Turn the general purpose knob or use the
main-menu arrow keys to select each letter. Press Enter Char from the main
menu to enter each letter. When you have entered the name, press the side
menu OK Accept item. (See Figure 3-30)
Confirm Delete
To turn on or off the confirm delete message, toggle the side menu Confirm
Delete button.
When the confirm delete option is OFF, the digitizing oscilloscope can im-
mediately delete files or directories. When the confirm option is ON, the
digitizing oscilloscope warns you before it deletes files and gives you a
chance to reconsider
Overwrite Lock
To turn on or off the file overwrite lock, toggle the side menu Overwrite Lock
button.
When overwrite lock is on, the digitizing oscilloscope will not permit you to
write over an existing file of the same name. An important reason to allow
overwriting is to let you write files using a target file name that contains wild
card characters (“?”). This means the digitizing oscilloscope creates sequen-
tial files whose names are similar except for the sequential numbers that go in
the real name in the place of the question marks.
Format
To format a 720 Kbyte or 1.44 Mbyte disk, turn the general purpose knob until
it scrolls the cursor over the name of the drive to format in. (fd0:) Then, press
the side menu Format button.
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Hardcopy
You can get a copy of the digitizing oscilloscope display by using the hardco-
py feature. Depending on the output format you select, you create either an
image or a plot. Images are direct bit map representations of the digitizing
oscilloscope display. Plots are vector (plotted) representations of the display.
Different hardcopy devices use different formats. The digitizing oscilloscope
supports the following formats:
Hardcopy Formats
HP Thinkjet inkjet printer
HP Deskjet inkjet printer
HP Laserjet laser printer
Epson
DPU-411/II portable thermal printer
DPU-412 portable thermal printer
PCX (PC Paintbrush)
PCX Color (PC Paintbrush) (TDS 524A & TDS 544A)
TIFF (Tag Image File Format)
BMP Mono (Microsoft Windows file format)
BMP Color (Microsoft Windows file format) (TDS 524A & TDS 544A)
RLE Color (Microsoft Windows color image file format – compressed)
(TDS 524A & TDS 544A)
EPS Mono Image (Encapsulated Postscript, mono-image)
EPS Color Image (Encapsulated Postscript, color-image) (TDS 524A &
TDS 544A)
EPS Mono Plot (Encapsulated Postscript, mono-plot)
EPS Color Plot (Encapsulated Postscript, color-plot)
Interleaf
HPGL Color Plot
Some formats, particularly Interleaf, EPS, TIFF, PCX, BMP, and HPGL, are
compatible with various desktop publishing packages. That means you can
paste files created from the oscilloscope directly into a document on any of
those desktop publishing systems.
EPS Mono and Color formats are compatible with Tektronix Phaser Color
Printers, HPGL is compatible with the Tektronix HC100 Plotter, and Epson is
compatible with the Tektronix HC220 Printer.
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Hardcopy
Before you make a hardcopy, you need to set up communications and hard-
copy parameters. This discussion assumes that the hardcopy device is
already connected to the GPIB port on the rear panel. If that is not the case
see Connection Strategies on page 3-63.
Operation
Setting Communication Parameters
To set up the communication parameters to talk to a printer attached directly
to the oscilloscope GPIB port:
Press SHIFT UTILITY ➞ System (main) ➞ I/O (pop-up) ➞ Port ➞
GPIB (pop-up) ➞ Configure (main) ➞ Hardcopy (Talk Only) (side).
To set up the communication parameters to talk to a printer attached directly
to the oscilloscope RS-232 port:
Press SHIFT UTILITY ➞ System (main) ➞ I/O (pop-up) ➞ Port ➞
RS232 (pop-up) ➞ Hardware Setup (main).
Press the side-menu Baud Rate, Stop Bits, Parity and Hard Flagging items
and enter data as desired to match the hardcopy device
(see Figure 3-31).
Press Software Setup (main) and toggle the side-menu Soft Flagging item
to turn software flagging on or off as desired.
Figure 3-31: Utility Menu — System I/O
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Hardcopy
Setting Hardcopy Parameters
To specify the hardcopy format, layout, and type of port using the hardcopy
menu:
1. Press SHIFT HARDCOPY MENU to bring up the Hardcopy menu.
2. Press Format (main) ➞ Thinkjet, Deskjet, Laserjet, Epson, DPU-411,
DPU-412, PCX, PCX Color (TDS 544A), TIFF, BMP Mono, BMP Color
(TDS 544A), RLE Color (TDS 544A), EPS Mono Img, EPS Color
Image (TDS 544A), EPS Mono Plt, EPS Color Plt, Interleaf, or HPGL
(side). (Press –more– (side) to see all of these format choices.)
3. Press SHIFT HARDCOPY MENU ➞ Layout (main) ➞ Landscape or
Portrait (side) (see Figure 3-32).
Landscape Format
Portrait Format
Figure 3-32: Hardcopy Formats
4. Press SHIFT HARDCOPY MENU ➞ Port (main) to specify the output
channel to send your hardcopy through. The choices are GPIB, RS-232,
Centronics, and File (RS-232, Centronics, and File are optional on the
TDS 520A & TDS 540A).
If you choose File, the file-list scrollbar will appear. Turn the general
purpose knob to select the desired file.
5. For hardcopy formats that support palettes, press SHIFT HARDCOPY
MENU ➞ Palette (main) ➞ Hardcopy or Current (side). Choose Hardco-
py to have the hardcopy created using the Hardcopy Preview palette in
the Color Palette menu. The default settings for this palette provide a
white background. Choose Current to have the hardcopy created in colors
that closely match the current display.
Printing the Hardcopy
You can print a single hardcopy or send additional hardcopies to the spool
(queue) while waiting for earlier hardcopies to finish printing. To print your
hardcopy(ies):
Press HARDCOPY to print your hardcopy.
While the hardcopy is being sent to the printer, the oscilloscope will display
the message “Hardcopy in process — Press HARDCOPY to abort.”
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Hardcopy
To stop and discard the hardcopy being sent, press HARDCOPY again while
the hardcopy in process message is still on screen.
To add additional hardcopies to the printer spool, press HARDCOPY again
after the hardcopy in process message is removed from the screen.
You can add hardcopies to the spool until it is full. When the spool is filled by
adding a hardcopy, the message “Hardcopy in Process — Press HARDCOPY
to abort” remains displayed. You can abort the last hardcopy sent by pressing
the button while the message is still displayed. When the printer empties
enough of the spool to finish adding the last hardcopy it does so and then
removes the message.
To remove all hardcopies from the spool:
Press SHIFT HARDCOPY MENU ➞ Clear Spool (main) ➞ OK Confirm
Clear Spool (side).
This oscilloscope takes advantage of any unused RAM when spooling hard-
copies to printers. The size of the spool is, therefore, variable. The number of
hardcopies that can be spooled depends on three variables:
the amount of unused RAM
the hardcopy format chosen
the complexity of the display
Although not guaranteed, usually about 2.5 hardcopies can be spooled before
the oscilloscope must wait to send the rest of the third copy.
Date/Time Stamping Your Hardcopy
You can display the current date and time on screen so that they appear on
the hardcopies you print. To date and time stamp your hardcopy:
1. Press DISPLAY ➞ Readout Options (main) ➞ Display Date and Time
(side) to toggle the setting to On.
2. Press Clear Menu to remove the menu from the display so the date and
time can be displayed (see Figure 3-33). (The date and time are removed
from the display when menus are displayed.)
3. Press HARDCOPY to print your date/time stamped hardcopy.
If you need to set the date and time of the oscilloscope:
4. Press SHIFT UTILITY ➞ Config (pop-up) ➞ Set Date & Time (main) ➞
Year, Day Month, Hour, or Minute.
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Hardcopy
Date and Time Display
Figure 3-33: Date and Time Display
5. Use the general purpose knob or the keypad to set the parameter you
have chosen to the value desired. (The format when using the keypad is
rd
day.month. For example, use 23.6 for the 23 of June.)
6. Repeat steps 4 and 5 to set other parameters as desired.
7. Press OK Enter Date/Time (side) to put the new settings into effect. This
sets the seconds to zero.
NOTE
When setting the clock, you can set to a time slightly later than the
current time and wait for it to catch up. When current time catches
up to the time you have set, pressing Ok Enter Date/Time (side)
synchronizes the set time to the current time.
8. Press CLEAR MENU to see the date/time displayed with the new set-
tings.
9. Press HARDCOPY to print your date/time stamped hardcopy.
The ability of the digitizing oscilloscope to print a copy of its display in many
formats (see page 3-59) gives you flexibility in choosing a hardcopy device. It
also makes it easier for you to place oscilloscope screen copies into a desk-
top publishing system.
Connection
Strategies
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Hardcopy
Strategies for actually printing a copy include:
Send output straight to a printer/plotter.
Send the data to a computer to print from there and/or to import into your
favorite desktop publishing or other application package.
Send your data to a floppy disk file (optional on the TDS 520A &
TDS 540A) for later printing from a computer capable of reading the
MS-DOS compatible floppy disk.
Printing Directly to a Hardcopy Device
You can connect the digitizing oscilloscope directly to a hardcopy device (see
Figure 3-34). An example of a GPIB hardcopy device is the Tektronix HC100
Plotter. Many printers, such as the Tektronix HC220, use Centronics inter-
faces. Many hardcopy devices, including the HC100 with option 03, provide
RS-232 support.
Digitizing
Oscilloscope
Hardcopy Device
(e.g., Tek HC100)
GPIB, RS-232, or Centronics Cable
Figure 3-34: Connecting the Digitizing Oscilloscope Directly to the
Hardcopy Device
Using a Controller
You can put a controller with two ports between the digitizing oscilloscope and
the hardcopy device (see Figure 3-35). Use a GPIB port to remotely request
and receive a hardcopy from the digitizing oscilloscope. Use an RS-232 or a
Centronics port on the controller to print output.
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Hardcopy
GPIB Cable
Centronics or
RS-232 Cable
PC Compatible
Digitizing
Oscilloscope
Hardcopy Device
Figure 3-35: Connecting the Digitizing Oscilloscope and Hardcopy
Device Via a PC
If your controller is PC-compatible and it uses the Tektronix GURU or
S3FG210 (National Instruments GPIB-PCII/IIA) GPIB package, you can
operate this setup as follows:
1. Use the MS-DOS cd command to move to the directory that holds the
software that came with your GPIB board. For example, if you installed
the software in the GPIB-PC directory, type: cd GPIB-PC
2. Run the IBIC program that came with your GPIB board. Type: IBIC
3. Type: IBFIND DEV1 where “DEV1” is the name for the digitizing oscillo-
scope you defined using the IBCONF.EXE program that came with the
GPIB board.
NOTE
If you defined another name then, of course, use it instead of
“DEV1”. Also, remember that the device address of the digitizing
oscilloscope as set with the IBCONF.EXE program should match
the address set in the digitizing oscilloscope Utility menu (typically,
use “1”).
4. Type: IBWRT “HARDCOPY START” Be sure the digitizing oscilloscope
Utility menu is set to Talk/Listen and not Hardcopy (Talk Only) or you
will get an error message at this step. Setting the digitizing oscilloscope
Utility menu was described in the start of this Hardcopy section under the
heading Setting Communication Parameters. Be sure to set the controller
time-out longer than the time required to transfer the hardcopy.
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Hardcopy
5. Type: IBRDF <Filename>where <Filename> is a valid DOS file name
you want to call your hardcopy information. It should be 8 characters
long with up to a 3 character extension. For example, you could type
“ibrdf screen1”.
6. Exit the IBIC program by typing: EXIT
7. Type: COPY <Filename> <Output port> </B> where <Filename> is the
name you defined in step 5 and <Output port> is the PC output port your
hardcopy device is connected to (such as LPT1 or LPT2). Copy the data
from your file to your hardcopy device. First, ensure your printer or plotter
is properly attached to your PC. Then copy the file. For example, if your
file is called screen1 and your printer is attached to the lpt1 parallel port,
type “copy screen1 lpt1: /B”.
NOTE
If you transmit hardcopy files across a computer network, use a
binary (8-bit) data path.
Your hardcopy device should now print a picture of the digitizing oscilloscope
screen.
See Remote Communication, on page 3-126.
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Help
The on-line help system provides brief information about each of the digitizing
oscilloscope controls.
To use the on-line help system:
Operation
Press HELP to provide on-screen information on any front panel button, knob
or menu item (see Figure 3-36).
When you press that button, the instrument changes mode to support on-line
help. Press HELP again to return to regular operating mode. Whenever the
oscilloscope is in help mode, pressing any button (except HELP or SHIFT),
turning any knob, or pressing any menu item displays help text on the screen
that discusses that control.
The menu selections that were displayed when HELP was first pressed re-
main on the screen. On-line help is available for each menu selection dis-
played at the time the HELP button was first pressed. If you are in help mode
and want to see help on selections from non-displayed menus, you first exit
help mode, display the menu you want information on, and press HELP again
to re-enter help mode.
Figure 3-36: Initial Help Screen
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Horizontal Control
You can control the horizontal part of the display (the time base) using the
horizontal menu and knobs.
By changing the horizontal scale, you can focus on a particular portion of a
waveform. By adjusting the horizontal position, you can move the waveform
right or left to see different portions of the waveform. That is particularly
useful when you are using larger record sizes and cannot view the entire
waveform on one screen.
Horizontal Knobs
To change the horizontal scale and position, use the horizontal POSITION
and horizontal SCALE knobs (see Figure 3-37). These knobs manage the
time base and horizontal waveform positioning on the screen. When you use
either the horizontal SCALE or POSITION knobs, you affect all the waveform
records displayed.
When you use either the horizontal SCALE or POSITION knobs, you affect
all displayed waveform records. If you want the POSITION knob to move
faster, press the SHIFT button. When the light above the shift button is on
and the display says Coarse Knobs in the upper right corner, the POSITION
knob speeds up significantly.
Figure 3-37: Horizontal Controls
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Horizontal Control
At the top of the display, the Record View shows the size and location of the
waveform record and the location of the trigger relative to the display (see
Figure 3-38). The Time Base readout at the lower right of the display shows
the time/division settings and the time base (main or delayed) being referred
to (see Figure 3-38).
Horizontal Readouts
Record View Readout
Time Base Readout
Figure 3-38: Record View and Time Base Readouts
The Horizontal menu lets you select either a main or delayed view of the time
base for acquisitions. It also lets you set the record length, set the trigger
position, and change the position or scale.
Horizontal Menu
Main and Delayed Time Base
To select between the Main and Delayed views of the time base:
Press HORIZONTAL MENU ➞ Time Base (main) ➞ Main Only, Intensified,
or Delayed Only (side).
By pressing Intensified, you display a colored or intensified zone that shows
where the delayed trigger record length could occur relative to the main
trigger. The start of the zone corresponds to the possible start point of the
delayed trigger. The end of the zone corresponds to the end of the delayed
view of the time base.
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Horizontal Control
You also can select Delayed Runs After Main or Delayed Triggerable. For
more information on how to use these two menu items, see Delayed Trigger-
ing on page 3-22.
Trigger Position
To define how much of the record will be pretrigger and how much posttrigger
information using the Trigger Position menu item:
Press HORIZONTAL MENU ➞ Trigger Position (main) ➞ Set to 10%, Set
to 50%, or Set to 90% (side), or use the general purpose knob or the keypad
to change the value.
Record Length and Fit To Screen
To set the waveform record length, press HORIZONTAL MENU ➞ Record
Length (main). The side menu lists various discrete record length choices.
NOTE
If you selected the longest record length available in the Horizontal
menu, then you cannot select Hi Res as your acquisition mode. This
is because Hi Res mode uses twice the acquisition memory that the
other acquisition modes use. If Hi Res and the longest horizontal
record length were allowed to be selected at the same time, the
oscilloscope would run out of memory.
To fit an acquired waveform to the visible screen, regardless of record length,
press HORIZONTAL MENU ➞ Record Length (main). Then toggle Fit to
Screen to ON from the side menu. This provides similar functionality to being
in zoom mode and changing the time/division until the waveform fits the
screen. To turn off this feature, toggle Fit to Screen to OFF.
Horizontal Scale
To change the horizontal scale (time per division) numerically in the menu
instead of using the Horizontal SCALE knob:
Press HORIZONTAL MENU ➞ Horiz Scale (main) ➞ Main Scale or
Delayed Scale (side), and use the keypad or the general purpose knob to
change the scale values.
Horizontal Position
You can set the horizontal position to specific values in the menu instead of
using the Horizontal POSITION knob.
Press HORIZONTAL MENU ➞ Horiz Pos (main) ➞ Set to 10%, Set to 50%
or Set to 90% (side) to choose how much of the waveform will be displayed
to the left of the display center.
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Horizontal Control
You can also control whether changing the horizontal position setting affects
all displayed waveforms, just the live waveforms, or only the selected wave-
form. The Horizontal Lock setting in the Zoom menu determines which wave-
forms the horizontal position knob adjusts whether zoom is on or not. Specifi-
cally, it acts as follows:
None — only the waveform currently selected can be zoomed and posi-
tioned horizontally
Live — all channels (including AUX channels for the TDS 524A &
TDS 620A) can be zoomed and positioned horizontally at the same time
All — all waveforms displayed (channels, math, and/or reference) can be
zoomed and positioned horizontally at the same time
See Zoom, on page 3-162 for the steps to set the horizontal lock feature.
If you are using the FastFrame mode, you can jump to the desired frame.
Press HORIZONTAL MENU ➞ Horizontal Position (main) ➞ Frame and
use the general purpose knob or keypad to enter the frame to jump to. After
you press Enter, that frame should appear on the display.
FastFrameTM
You can define and enable FastFrame (also called “segmented memory”).
This feature lets you capture multiple acquisitions in the acquisition memory
of a single channel.
Press HORIZONTAL MENU ➞ FastFrame Setup (main) ➞ FastFrame
(side) to toggle on or off the use of FastFrame (see Figure 3-39).
Press Frame Length or Frame Count (side) and use the general purpose
knob to enter FastFrame parameters. The frame length refers to the number
of samples in each acquisition. The frame count refers to the number of
acquisitions to store in the acquisition memory of the channel. The digitizing
oscilloscope will set the record length to a value greater than or equal to the
product of the frame count and the frame length. If the product exceeds the
maximum available record length, the digitizing oscilloscope will reduce the
frame length or frame count in size such that the product will fit the record
length.
Press Horiz Pos (main), then Frame (side), and use the general purpose
knob to enter the number of a specific frame to view.
If you shift the waveform right or left with the front-panel HORIZONTAL
POSITION knob, the window next to the side-menu Frame button will indicate
the frame number of the waveform at the center of the screen.
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Horizontal Control
Figure 3-39: Horizontal Menu — FastFrame Setup
FastFrame Interactions — Envelope, Average, and HiRes form the
envelope or average following the last frame of the concatenated record. For
example, if average or HiRes acquisition modes are selected and the frame
count is 10, segments 1 through 10 will show sample or HiRes frames, and
frame 11 will show the average of frames 1 through 10. If there is not room for
one additional frame, the envelope or average of the frames replaces the
display of the last acquired frame.
Average and envelope counts have no affect in FastFrame.
You can press RUN/STOP to terminate a FastFrame sequence. If any frames
were acquired, they are displayed. If no frames were acquired, the previous
FastFrame waveform is displayed.
Because FastFrame waveforms contain many triggers, trigger position indica-
tors are removed from both the waveform and the record view when the
selected channel, reference, or math waveform is a FastFrame waveform.
In Equivalent Time, FastFrame defaults to off.
See Scaling and Positioning Waveforms, on page 2-25.
See Delayed Triggering, on page 3-22.
See Zoom, on page 3-162.
For More
Information
See Display Modes, on page 3-28.
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Limit Testing
Limit testing provides a way to automatically compare each incoming or math
waveform against a template waveform. You set an envelope of limits around
a waveform and let the digitizing oscilloscope find waveforms that fall outside
those limits (see Figure 3-40). When it finds such a waveform, the digitizing
oscilloscope can generate a hardcopy, ring a bell, stop and wait for your input,
or any combination of these actions.
Figure 3-40: Comparing a Waveform to a Limit Template
When you use the limit testing feature, the first task is to create the limit test
template from a waveform. Next, specify the channel to compare to the
template. Then you specify the action to take if incoming waveform data
exceeds the set limits. Finally, turn limit testing on so that the parameters you
have specified will take effect.
To access limit testing:
Operation
Press SHIFT ACQUIRE MENU to bring up the Acquire menu.
Create Limit Test Template
To use an incoming or stored waveform to create the limit test template, first
select a source.
1. Press Create Limit Test Template (main) ➞ Template Source (side) ➞
Ch1, Ch2, Math1, Math2, Math3, Ref1, Ref2, Ref3, or Ref4 (side). (See
Figure 3-41).
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Limit Testing
NOTE
The template will be smoother if you acquire the template waveform
using Average acquisition mode. If you are unsure how to do this,
see Acquisition Modes on page 3-7.
Once you have selected a source, select a destination for the template.
2. Press Template Destination (side) ➞ Ref1, Ref2, Ref3, or Ref4.
Figure 3-41: Acquire Menu — Create Limit Test Template
Now create the envelope by specifying the amount of variation from the
template that you will tolerate. Tolerance values are expressed in frac-
tions of a major division. They represent the amount by which incoming
waveform data can deviate without having exceeded the limits set in the
limit test. The range is from 0 (the incoming waveform must be exactly
like the template source) to 5 major divisions of tolerance.
3. Press
Limit (side). Enter the vertical (voltage) tolerance value using
the general purpose knob or keypad.
4. Press
Limit (side). Enter the horizontal (time) tolerance value using
the general purpose knob or keypad.
5. When you have specified the limit test template as you wish, press OK
Store Template (side). This action stores the specified waveform in the
specified destination, using the specified tolerances. Until you have done
so, the template waveform has been defined but not created.
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Limit Testing
If you wish to create another limit test template, store it in another des-
tination to avoid overwriting the template you have just created.
If you wish to view the template you have created, press the MORE
button. Then press the button corresponding to the destination reference
memory you have used. The waveform appears on the display.
NOTE
To view the waveform data as well as the template envelope, it
might be useful to select the Dots display style (see Display Modes
on page 3-28).
Limit Test Sources
Now specify the channel that will acquire the waveforms to be compared
against the template you have created.
1. Press SHIFT ACQUIRE MENU ➞ Limit Test Sources (main) ➞
Compare Ch1 to, Compare Ch2 to, Compare Ch3 to, Compare Ch4
to, Compare Math1 to, Compare Math2 to or Compare Math3 to
(side).
2. Once you have selected one of the four channels or a math waveform as
a waveform source from the side menu, press the same side menu button
to select one of the reference memories in which you have stored a
template.
Valid selections are any of the four reference waveforms Ref1 through
Ref4 or None. Choosing None turns limit testing off for the specified
channel.
NOTE
Specify the same reference memory you chose as the template
destination if you wish to use the template you just created.
If you have created more than one template, you can compare one
channel to one template and the other channel to another template.
Limit Test Setup
Now specify the action to take if waveform data exceeds the limits set by the
limit test template.
1. Press SHIFT ACQUIRE MENU ➞ Limit Test Setup (main) to bring up a
side menu of possible actions.
2. Ensure that the side button corresponding to the desired action reads
ON.
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Limit Testing
If you want to send a hardcopy command when waveform data
exceeds the limits set, toggle Hardcopy if Condition Met (side) to
ON. You can set the hardcopy system to send the hardcopy to the file
system (optional on the TDS 620A & TDS 640A). (Do not forget to
set up the hardcopy system. See Hardcopy on page 3-59 for details.)
If you want the bell to ring when waveform data exceeds the limits
set, toggle Ring Bell if Condition Met (side) to ON.
If you want the digitizing oscilloscope to stop when waveform data
exceeds the limits set, toggle Stop After Limit Test Condition Met
(side) to ON.
NOTE
The button labeled Stop After Limit Test Condition Met corre-
sponds to the Limit Test Condition Met menu item in the Stop
After main menu. You can turn this button on in the Limit Test
Setup menu, but you cannot turn it off. In order to turn it off, press
Stop After and specify one of the other choices in the Stop After
side menu.
Now that you have set up the instrument for limit testing, you must turn
limit testing on in order for any of these actions to take effect.
3. Ensure that Limit Test (side) reads ON. If it reads OFF, press Limit Test
(side) once to toggle it to ON.
When you set Limit Test to ON, the digitizing oscilloscope compares
incoming waveforms against the waveform template stored in reference
memory according to the settings in the Limit Test Sources side menu.
You can compare a single waveform against a single template, more than one
waveform against a single template, or more than one waveform with each
one compared against its own template. How Limit Test operates depends on
which type of these comparisons you choose.
Single and Multiple
Waveforms
Single Waveform Comparisons
When making a single waveform versus a single template comparison, con-
sider the following operating characteristics:
The waveform will be repositioned horizontally to move the first sample in
the waveform record that is outside of template limits to center screen.
The position of the waveform template will track that of the waveform.
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Limit Testing
Multiple Waveform Comparisons
When comparing one or more waveforms, each against a common template
or against its own template, consider the following operating characteristics:
You should set Horizontal Lock to None in the Zoom side menu (push
ZOOM and press (repeatedly) Horizontal Lock to None).
With horizontal lock set as just described, the oscilloscope will reposition
each waveform horizontally to move the first sample in the waveform
record that is outside of template limits to center screen.
If you are comparing each waveform to its own template, the position of
each waveform template will track that of its waveform.
If you are comparing two or more waveforms to a common template, that
template will track the position of the failed waveform. If more than one
waveform fails during the same acquisition, the template will track the
position of the waveform in the highest numbered channel. For example,
CH 2 is higher than CH 1.
See Acquisition, on page 2-19.
See Acquisition Modes, on page 3-3.
See Display Modes, on page 3-28.
See Zoom, on page 3-162.
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Logic Triggering
There are two classes of logic triggering: pattern and state.
A pattern trigger occurs when the logic inputs to the logic function you select
cause the function to become TRUE (or at your option FALSE). When you
use a pattern trigger, you define:
The precondition for each logic input — logic high, low, or do not care (the
logic inputs are channels 1, 2, 3, and 4 for the TDS 640A & TDS 644A
and 1, 2, Aux 1, and Aux 2 for the TDS 620A & TDS 524A)
The Boolean logic function — select from AND, NAND, OR, and NOR
The condition for triggering — whether the trigger occurs when the Bool-
ean function becomes TRUE (logic high) or FALSE (logic low), and
whether the TRUE condition is time qualified (see page 3-83).
A state trigger occurs when the logic inputs to the logic function cause the
function to be TRUE (or at your option FALSE) at the time the clock input
changes state. When you use a state trigger, you define:
The precondition for each logic input, channels 1, 2, and 3 for the
TDS 640A & TDS 644A (1, 2, and Ax1 on the TDS 620A & TDS 524A)
The direction of the state change for the clock input, channel 4 (Aux 2 for
the TDS 620A & TDS 524A)
The Boolean logic function — select from clocked AND, NAND, OR, and
NOR
The condition for triggering — whether the trigger occurs when the Bool-
ean function becomes TRUE (logic high) or FALSE (logic low)
Table 3-4 on page 3-80 lists the preconditions required for each logic function
to issue a pattern or state logic trigger.
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Logic Triggering
At the bottom of the display, the Trigger readout shows some of the key
parameters of the logic trigger (see Figure 3-42).
Logic Trigger
Readouts
Ch 1, 2, 3 Inputs = High, Don’t Care, High
Ch 4 Input =
Rising Edge
Trigger Class = State
Logic = OR
Figure 3-42: Logic Trigger Readouts
NOTE
When Logic is the selected trigger type, the threshold levels that
help determine triggering are set for each channel individually in the
Set Thresholds menu. Therefore, the Trigger Level readout will
disappear on the display and the Trigger Level knob can be used
to set the threshold level while the Main Trigger menu is set to
Logic.
Table 3-4 lists the definitions for the four types of logic functions available.
Keep in mind the following operating modes for the two classes, pattern and
state, of logic triggers as you apply the definitions.
Definitions
Pattern — At the end of trigger holdoff, the oscilloscope samples the inputs
from all the channels. The oscilloscope then triggers if the conditions defined
in Table 3-4 are met. (Goes TRUE or Goes FALSE must be set in the Trig-
ger When menu. The other settings in that menu are described in Define a
Time Qualified Pattern Trigger on page 3-83.)
State — At the end of trigger holdoff, the oscilloscope waits until the edge of
channel 4 (Aux 2 on the TDS 620A & TDS 524A) transitions in the specified
direction. At that point, the oscilloscope samples the inputs from the other
channels and triggers if the conditions defined in Table 3-4 are met.
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Logic Triggering
Table 3-4: Logic Triggers
State Definition
1,2
Pattern
AND
Clocked AND
If all the preconditions selected
for the logic inputs are true,
3
then the oscilloscope triggers.
NAND
Clocked NAND If not all of the preconditions se-
3
lected for the logic inputs are
true, then the oscilloscope trig-
gers.
OR
Clocked OR
If any of the preconditions se-
lected for the logic inputs are
3
true, then the oscilloscope trig-
gers.
NOR
Clocked NOR
If none of the preconditions se-
lected for the logic inputs are
3
true, then the oscilloscope trig-
gers.
1
Note that for State class triggers, the definition must be met at the time the clock input
changes state. See the descriptions for Pattern and State in this section.
2
The definitions given here are correct for the Goes True setting in the Trigger When menu.
If that menu is set to Goes False, swap the definition for AND with that for NAND and for OR
with NOR for both pattern and state classes.
3
The logic inputs are channels 1, 2, 3, and 4 for the TDS 640A & TDS 644A and 1, 2, Aux 1
and Aux 2 for the TDS 620A & TDS 524A when using Pattern Logic Triggers. For State Logic
Triggers, channel 4 (Aux 2 for the TDS 620A & TDS 524A) becomes the clock input, leaving
the remaining channels as logic inputs.
The Logic Trigger menu (Figure 3-43) lets you select when to trigger (true or
false), set the thresholds for each channel, select the mode (auto or normal),
and adjust the holdoff.
Operations Common
to Pattern and State
Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞ Class (main) ➞
Pattern or State (pop-up).
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Logic Triggering
Figure 3-43: Logic Trigger Menu
Trigger When
This menu item lets you determine if the oscilloscope will trigger when the
logic condition is met (Goes TRUE) or when the logic condition is not met
(Goes FALSE). (The True when less than and True when greater than
menu items are only used for pattern logic triggering and are covered on
page 3-83.)
Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞ Class (main) ➞
Pattern or State (pop-up) ➞ Trigger When (main) ➞ Goes TRUE or Goes
FALSE (side).
Set Thresholds
To set the logic threshold for each channel:
1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞
Class (main) ➞ Pattern or State (pop-up) ➞ Set Thresholds (main) ➞
Ch1, Ch2, Ch3 (Ax1 on the TDS 620A & TDS 524A), or Ch4 (Ax2 on the
TDS 620A & TDS 524A) (side).
2. Use the MAIN TRIGGER LEVEL knob, the general purpose knob, or the
keypad to set each threshold.
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Logic Triggering
Mode & Holdoff
You can change the holdoff time and select the trigger mode using this menu
item.
1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞
Class (main) ➞ Pattern or State (pop-up) ➞ Mode & Holdoff (main) ➞
Auto or Normal (side).
In Auto mode the oscilloscope acquires a waveform after a specific
time has elapsed even if a trigger does not occur. The amount of time
the oscilloscope waits depends on the time base setting.
In Normal mode the oscilloscope acquires a waveform only if there is
a valid trigger.
2. Press Holdoff (side). Enter the value in percent using the general pur-
pose knob or the keypad.
Depending on whether you chose the class Pattern or State, there are differ-
ent menus for defining the channel inputs and the combinational logic.
When you select Pattern, the oscilloscope will trigger on a specified logic
combination of the four input channels. See page 3-80 for details on opera-
tions common to both pattern and state triggers.
Pattern Operations
Define Inputs
To set the logic state for each of the input channels (Ch1, Ch2, ...):
1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞
Class (main) ➞ Pattern (pop-up) ➞ Define Inputs (main) ➞ Ch1, Ch2,
Ch3, or Ch4 (side). (On the TDS 620A & TDS 524A, Ch3 and Ch4 are
replaced by Ax1 and Ax2.)
2. Repeatedly press each input selected in step 1 to choose either High (H),
Low (L), or Don’t Care (X) for each channel.
Define Logic
To choose the logic function you want applied to the input channels (see page
3-79 for definitions of the logic functions for both pattern and state triggers):
Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞ Class (main) ➞
Pattern (pop-up) ➞ Define Logic (main) ➞ AND, OR, NAND, or NOR (side).
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Logic Triggering
Define a Time Qualified Pattern Trigger
You can also time qualify a pattern logic trigger. That is, you specify a time
that the boolean logic function (AND, NAND, OR, or NOR) must be TRUE
(logic high). You also choose the type of time qualification (greater or less
than the time limit specified) as well as the time limit using the Trigger When
menu selection.
1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞
Class (main) ➞ Pattern (pop-up) ➞ Trigger When (main) ➞ True for
less than or True for more than (side).
2. Use the knob and keypad to set the time in the side menu.
When you select True for less than and specify a time using the general
purpose knob, the input conditions you specify must drive the logic function
high (TRUE) for less than the time you specify. Conversely, True for more
than requires the boolean function to be TRUE for longer than the time you
specify.
Note the position of the trigger indicator in Figure 3-44. Triggering occurs at
the point the logic function you specify is determined to be true within the time
you specify. The digitizing oscilloscope determines the trigger point in the
following manner:
It waits for the logic condition to become true
It starts timing and waits for the logic function to become false
It compares the times and, if the time TRUE is longer (for True for more
than) or shorter (for True for less than), then it triggers a waveform
display at the point the logic condition became false. This time can be,
and usually is, different from the time set for True for more than or True
for less than.
In Figure 3-44, the delay between the vertical bar cursors is the time the logic
function is TRUE. Since this time is more (216 s) than that set in the True
for more than menu item (150 s), the oscilloscope issues the trigger at that
point, not at the point at which it has been true for 216 s.
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Logic Triggering
Time Logic Function is TRUE
Logic Function (AND) Becomes TRUE
Logic Function Becomes FALSE and
Triggers Acquisition
Time Logic Function Must be TRUE
Figure 3-44: Logic Trigger Menu — Time Qualified TRUE
When you select State logic triggering, the oscilloscope uses channel 4
(Aux 2 on the TDS 620A & TDS 524A) as a clock for a logic circuit made from
the rest of the channels. See page 3-80 for details on operations common to
both pattern and state triggers.
State Operations
The state trigger logic works as follows: the oscilloscope waits until the fourth
channel meets the selected slope and voltage threshold. It then checks the
logic function applied to the first three channels, and if the function condition
is as specified in the the Trigger When menu (Goes TRUE or Goes FALSE)
a trigger occurs.
Define Inputs
To set the logic state for each of the input channels (Ch1, Ch2, ...):
1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞
Class (main) ➞ State (pop-up) ➞ Define Inputs (main).
2. Choose either High (H), Low (L), or Don’t Care (X) (side) for the first
three channels. The choices for Ch4 (Aux 2 on the TDS 620A &
TDS 524A) are rising edge and falling edge.
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Logic Triggering
Define Logic
To choose the type of logic function you want applied to the input channels:
Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞ Class (main) ➞
State (pop-up) ➞ Define Logic (main) ➞ AND, OR, NAND, or NOR (side).
See Triggering, on page 2-13.
See Triggering, on page 3-142.
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Measurement System
There are various ways to measure properties of waveforms. You can use
graticule, cursor, or automatic measurements. This section describes auto-
matic measurements; cursors and graticules are described elsewhere. (See
Cursor Measurements on page 3-17 and Measurements on page 2-30.)
Automatic measurements are generally more accurate and quicker than, for
example, manually counting graticule divisions. The oscilloscope will continu-
ously update and display these measurements. (There is also a way to dis-
play all the measurements at once — see Snapshot of Measurements on
page 3-95.)
Automatic measurements calculate waveform parameters from acquired data.
Measurements are performed over the entire waveform record or the region
specified by the vertical cursors, if gated measurements have been re-
quested. (See page 3-91 for a discussion of gated measurements.) They are
not performed just on the displayed portions of waveforms.
The TDS 600A Digitizing Oscilloscope provides you with 25 automatic mea-
surements (see Table 3-5).
The following are brief definitions of the automated measurements in the
digitizing oscilloscope (for more details see Appendix C: Algorithms,
page A-9).
Definitions
Table 3-5: Measurement Definitions
Name
Definition
Amplitude
Voltage measurement. The high value less the low value measured over the
entire waveform or gated region.
Amplitude = High – Low
Area
Voltage over time measurement. The area over the entire waveform or gated
region in volt-seconds. Area measured above ground is positive; area below
ground is negative.
Cycle Area
Voltage over time measurement. The area over the first cycle in the waveform,
or the first cycle in the gated region, in volt-seconds. Area measured above
ground is positive; area below ground is negative.
Burst Width
Cycle Mean
Cycle RMS
Timing measurement. The duration of a burst. Measured over the entire wave-
form or gated region.
Voltage measurement. The arithmetic mean over the first cycle in the waveform
or the first cycle in the gated region.
Voltage measurement. The true Root Mean Square voltage over the first cycle
in the waveform or the first cycle in the gated region.
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Measurement System
Table 3-5: Measurement Definitions (Cont.)
Definition
Name
Delay
Timing measurement. The time between the MidRef crossings of two different
traces or the gated region of the traces.
Fall Time
Timing measurement. Time taken for the falling edge of the first pulse in the
waveform or gated region to fall from a High Ref value (default = 90%) to a Low
Ref value (default =10%) of its final value.
Frequency
High
Timing measurement for the first cycle in the waveform or gated region. The
reciprocal of the period. Measured in Hertz (Hz) where 1 Hz = 1 cycle per sec-
ond.
The value used as 100% whenever High Ref, Mid Ref, and Low Ref values are
needed (as in fall time and rise time measurements). Calculated using either
the min/max or the histogram method. The min/max method uses the maxi-
mum value found. The histogram method uses the most common value found
above the mid point. Measured over the entire waveform or gated region.
Low
The value used as 0% whenever High Ref, Mid Ref, and Low Ref values are
needed (as in fall time and rise time measurements). May be calculated using
either the min/max or the histogram method. With the min/max method it is the
minimum value found. With the histogram method, it refers to the most com-
mon value found below the mid point. Measured over the entire waveform or
gated region.
Maximum
Mean
Voltage measurement. The maximum amplitude. Typically the most positive
peak voltage. Measured over the entire waveform or gated region.
Voltage measurement. The arithmetic mean over the entire waveform or gated
region.
Minimum
Voltage measurement. The minimum amplitude. Typically the most negative
peak voltage. Measured over the entire waveform or gated region.
Negative Duty
Cycle
Timing measurement of the first cycle in the waveform or gated region. The
ratio of the negative pulse width to the signal period expressed as a percent-
age.
Negative Over-
shoot
Voltage measurement. Measured over the entire waveform or gated region.
Negative Width
Timing measurement of the first pulse in the waveform or gated region. The
distance (time) between MidRef (default 50%) amplitude points of a negative
pulse.
Peak to Peak
Phase
Voltage measurement. The absolute difference between the maximum and
minimum amplitude in the entire waveform or gated region.
Timing measurement. The amount one waveform leads or lags another in time.
Expressed in degrees, where 360
cycle.
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Measurement System
Table 3-5: Measurement Definitions (Cont.)
Definition
Name
Period
Timing measurement. Time it takes for the first complete signal cycle to happen
in the waveform or gated region. The reciprocal of frequency. Measured in
seconds.
Positive Duty
Cycle
Timing measurement of the first cycle in the waveform or gated region. The
ratio of the positive pulse width to the signal period expressed as a percentage.
Positive Over-
shoot
Voltage measurement over the entire waveform or gated region.
Positive Width
Rise time
RMS
Timing measurement of the first pulse in the waveform or gated region. The
distance (time) between MidRef (default 50%) amplitude points of a positive
pulse.
Timing measurement. Time taken for the leading edge of the first pulse in the
waveform or gated region to rise from a Low Ref value (default = 10%) to a
High Ref value (default = 90%) of its final value.
Voltage measurement. The true Root Mean Square voltage over the entire
waveform or gated region.
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Measurement System
The readout area for measurements is on the right side of the waveform
Measurement Display
window. You can display and continuously update as many as four measure-
ments at any one time. When menus are displayed, the readouts appear in
the graticule area. If the menu area is empty, then the readouts are displayed
to the far right (see Figure 3-45).
Measurement Readout Area
Figure 3-45: Measurement Readouts
To use the automatic measurements you first need to obtain a stable display
of the waveform to be measured. Pressing AUTOSET may help. Once you
have a stable display, press MEASURE to bring up the Measure menu (see
Figure 3-46).
Operation
Selecting a Measurement
Measurements are made on the selected waveform. The measurement
display tells you the channel the measurement is being made on.
1. Press MEASURE ➞ Select Measrmnt (main).
2. Select a measurement from the side menu.
The following are hints on making automatic measurements:
You can only take a maximum of four measurements at a time. To
add a fifth, you must remove one or more of the existing measure-
ments.
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Measurement System
To vary the source for measurements, simply select the other channel
and then choose the measurements you want.
Be careful when taking automatic measurements on noisy signals.
You might measure the frequency of the noise and not the desired
waveform.
Your digitizing oscilloscope helps identify such situations by displaying a
low signal amplitude or low resolution warning message.
Figure 3-46: Measure Menu
Removing Measurements
The Remove Measrmnt selection provides explicit choices for removing
measurements from the display according to their readout position.
Measurement 1 is the top readout. Measurement 2 is below it, and so forth.
Once a measurement readout is displayed in the screen area, it stays in its
position even when you remove any measurement readouts above it. To
remove measurements:
1. Press MEASURE ➞ Remove Measrmnt (main).
2. Select the measurement to remove from the side menu. If you want to
remove all the measurements at one time, press All Measurements
(side).
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Measurement System
Gated Measurements
The gating feature lets you limit measurements to a specified portion of the
waveform. When gating is Off, the oscilloscope makes measurements over
the entire waveform record.
When gating is activated, vertical cursors are displayed. Use these cursors to
define the section of the waveform you want the oscilloscope to measure.
This is called the gated region.
1. Press MEASURE ➞ Gating (main) ➞ Gate with V Bar Cursors (side)
(see Figure 3-47).
Figure 3-47: Measure Menu — Gating
2. Using the general purpose knob, move the selected (the active) cursor.
Press SELECT to change which cursor is active.
Displaying the cursor menu and turning V Bar cursors off will not turn
gating off. (Gating arrows remain on screen to indicate the area over
which the measurement is gated.) You must turn gating off in the Gating
side menu.
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Measurement System
NOTE
Cursors are displayed relative to the selected waveform. If you are
making a measurement using two waveforms, this can be a source
of confusion. If you turn off horizontal locking and adjust the hori-
zontal position of one waveform independent of the other, the
cursors appear at the requested position with respect to the se-
lected waveform. Gated measurements remain accurate, but the
displayed positions of the cursors change when you change the
selected waveform.
High-Low Setup
The High-Low Setup item provides two choices for how the oscilloscope
determines the High and Low levels of waveforms. These are histogram and
min-max.
Histogram sets the values statistically. It selects the most common value
either above or below the mid point (depending on whether it is defining
the high or low reference level). Since this statistical approach ignores
short term aberrations (overshoot, ringing, etc.), histogram is the best
setting for examining pulses.
Min-max uses the highest and lowest values of the waveform record. This
setting is best for examining waveforms that have no large, flat portions at
a common value, such as sine waves and triangle waves — almost any
waveform except for pulses.
To use the high-low setup:
Press MEASURE ➞ High-Low Setup (main) ➞ Histogram or Min-Max
(side). If you select Min-Max, you may also want to check and/or revise
values using the Reference Levels main menu.
Reference Levels
Once you define the reference levels, the digitizing oscilloscope will use them
for all measurements requiring those levels. To set the reference levels:
1. Press MEASURE ➞ Reference Levels (main) ➞ Set Levels (side) to
choose whether the References are set in % relative to High (100%) and
Low (0%) or set explicitly in the units of the selected waveform (typically
volts). See Figure 3-48. Use the general purpose knob or keypad to enter
the values.
% is the default selection. It is useful for general purpose applica-
tions.
Units is helpful for setting precise values. For example, if you are
trying to measure specifications on an RS-232-C circuit, you can set
the levels precisely to RS-232-C specification voltage values by
defining the high and low references in units.
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Measurement System
2. Press High Ref, Mid Ref, Low Ref, or Mid2 Ref (side).
High Ref — Sets the high reference level. The default is 90%.
Mid Ref — Sets the middle reference level. The default is 50%.
Low Ref — Sets the low reference level. The default is 10%.
Mid2 Ref — Sets the middle reference level used on the second
waveform specified in the Delay or Phase Measurements. The default
is 50%.
Figure 3-48: Measure Menu — Reference Levels
Delay Measurement
The delay measurement lets you measure from an edge on the selected
waveform to an edge on another waveform. You access the Delay Measure-
ment menu through the Measure main menu:
Press MEASURE ➞ Select Measrmnt (main) ➞ Delay (side). This brings up
the Measure Delay main menu (see Figure 3-49).
Delay to — To select the waveform you want to measure to, use the main
menu item Delay to. The waveform you are measuring from is the selected
waveform.
1. Press MEASURE ➞ Select Measrmnt (main) ➞ Delay (side) ➞ Delay
To (main) ➞ Measure Delay to.
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Measurement System
2. Press Measure Delay to (side) repeatedly to choose the delay to wave-
form. The choices are Ch1, Ch2, Ch3, Ch4 (on the TDS 644A &
TDS 640A); Ch1, Ch2, Ax1, Ax2 (on the TDS 524A & TDS 620A); and
Math1, Math2, Math3, Ref1, Ref2, Ref3, and Ref4.
Figure 3-49: Measure Delay Menu — Delay To
Delay Edges — The main menu item Edges lets you specify which edges
you want the delayed measurement to be made between.
Press MEASURE ➞ Select Measrmnt (main) ➞ Delay (side) ➞
Edges (main). A side menu of delay edges and directions will appear.
Choose from one of the combinations displayed on the side menu.
The upper waveform on each icon represents the from waveform and the
lower one represents the to waveform.
The direction arrows on the choices let you specify a forward search on both
waveforms or a forward search on the from waveform and a backwards
search on the to waveform. The latter choice is useful for isolating a specific
pair of edges out of a stream.
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Measurement System
Creating the Delay Measurement — Once you have specified the
waveforms you are measuring between and which edges to use, you need to
notify the digitizing oscilloscope to proceed with the measurement.
Press Delay To (main) ➞ OK Create Measurement (side).
To exit the Measure Delay menu without creating a delay measurement,
press CLEAR MENU, which returns you to the Measure menu.
Sometimes you may want to see all of the automated measurements on
screen at the same time. To do so, use Snapshot. Snapshot executes all of
the single waveform measurements available on the selected waveform once
and displays the results. (The measurements are not continuously updated.)
All of the measurements listed in Table 3-5 on page 3-86 except for Delay
and Phase are displayed. (Delay and Phase are dual waveform measure-
ments and are not available with Snapshot.)
Snapshot of
Measurements
The readout area for a snapshot of measurements is a pop up display that
covers about 80% of the graticule area when displayed (see Figure 3-50). You
can display a snapshot on any channel or ref memory, but only one snapshot
can be displayed at a time.
Snapshot Display
Figure 3-50: Snapshot Menu and Readout
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Measurement System
To use snapshot, obtain a stable display of the waveform to be measured.
Pressing AUTOSET may help.
1. Press MEASURE ➞ SNAPSHOT (main).
2. Press either SNAPSHOT (main) or AGAIN (side) to take another snap-
shot.
NOTE
The snapshot display tells you the channel that the snapshot is
being made on.
3. Push Remove Measrmnt.
Considerations When Taking Snapshots
Be aware of the following items when using snapshot:
Be sure to display the waveform properly before taking a snapshot.
Snapshot does not warn you if a waveform is improperly scaled (clipped,
low signal amplitude, low resolution, etc.).
To vary the source for taking a snapshot, simply select another channel,
math, or ref memory waveform and then execute snapshot again.
A snapshot is taken on a single waveform acquisition (or acquisition
sequence). The measurements in the snapshot display are not continu-
ously updated.
Be careful when taking automatic measurements on noisy signals. You
might measure the frequency of the noise and not the desired waveform.
Note that pushing any button in the main menu (except for Snapshot) or
any front panel button that displays a new menu removes the snapshot
from display.
Use High-Low Setup (page 3-92), Reference Levels (page 3-92), and
Gated Measurements (page 3-91) with snapshot exactly as you would
when you display individual measurements from the Select Measrmnt
menu.
See Appendix B: Algorithms, on page A-9.
For More
Information
See Measurements, on page 2-30.
See Tutorial Example 3: Automated Measurements, on page 1-17.
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Probe Accessories
The probe you use and how you connect it to a signal source affect the
oscilloscope acquisition of the waveform record. Two important factors are
ground lead inductance (introduced by the probe) and the physical layout of
your circuit and component devices.
For an amplitude measurement to be meaningful, you must give the measure-
ment some point of reference. The probe offers you the capability of referenc-
ing the voltage at its tip to ground. To make your measurement as accurate
as possible, the probe ground lead should be connected to the ground refer-
ence.
Ground Lead
Inductance
However, when you touch your probe tip to a circuit, you are introducing new
resistance, capacitance, and inductance into the circuit (see Figure 3-51).
Probe
Tip Inductance L
R
t
source
Probe
in 10 M
Probe
10.0 pF
V
source
R
Ground Lead Inductance L
gl
Figure 3-51: A Probe Adds Resistance, Capacitance, and Inductance
For most circuits, the high input resistance of a passive probe has a negligible
effect on the signal. The series inductances represented by the probe tip and
ground lead, however, can result in a parasitic resonant circuit that may “ring”
within the bandwidth of the oscilloscope. Figure 3-52 shows the effect of the
same signal through the same probe with different ground leads.
Ringing and rise time degradation may be hidden if the frequency of the
induced ringing is beyond the bandwidth of the oscilloscope. If you know the
self-inductance (L) and capacitance (C) of your probe and ground lead, you
can calculate the approximate resonant frequency (f ) at which that parasitic
0
circuit will resonate:
Reducing the ground lead inductance will raise the resonant frequency.
Ideally, the inductance is low enough that the resulting frequency is above the
frequency at which you want to take measurements. For that purpose, the
probes include several accessories to help reduce ground lead inductance.
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Probe Accessories
4 Inch Ground Lead
Low-Inductance
Ground Lead
Figure 3-52: Signal Variation Introduced by Probe Ground Lead
(1 ns/division)
The following descriptions explain how to use many of the accessories that
came with your probe. Figure 3-53 shows both standard and optional probe
accessories and how they attach to your probe.
Standard Probe
Accessories
These accessories either reduce ground lead inductance or make it physically
easier to probe different kinds of circuits.
Standard probe accessories include the following items.
Retractable Hook Tip
The retractable hook tip attaches to your signal test point for hands-free
operation of the probe. The hook tip attaches to components having leads,
such as resistors, capacitors, and discrete semiconductors. You can also grip
stripped wire, jumpers, busses, and test pins with the retractable hook.
For maximum flexibility with the hook tip, use one of the six-inch ground
leads. For precise measurements at high frequency, however, long ground
leads may have too much inductance. In these cases you can use one of the
low-inductance probe tip configurations instead.
To remove the hook tip, simply pull it off the probe. Reinstall it by pushing it
firmly onto the ribbed ferrule of the probe tip (see Figure 3-53).
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Probe Accessories
Marker Ring
(Standard)
Marker Ring
(Standard)
Compact-to-Miniature
Probe Tip Adapter
(Optional)
IC Protector Tip
(Optional)
Probe Tip-to-Circuit
Board Adapter
(Standard)
Dual Lead Adapter
(Optional)
Probe Tip-to-Chassis
Adapter (Optional)
Slip-on
Ground Lead
(Standard)
Alligator Clip
Ground Lead
(Standard)
Retractable Hook Tip
(Standard)
TM
Low Inductance
Spring Tip (Optional)
KlipChip
(Standard)
Low Inductance
Ground Lead
(Standard)
Figure 3-53: Probe Accessories
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Marker Rings
The marker rings help you keep track of individual probes and signal sources
when you have a complicated test setup. Use the marker rings whenever you
want to identify a particular probe.
Long Ground Leads
Use long ground leads when a long reach is important and high-frequency
information is not. Long ground leads are ideal for quick troubleshooting when
you are looking for the presence or absence of a signal and are not con-
cerned with the precision of the measurement.
Because of the high inductance associated with long ground leads, you
should not use them for precise measurements above approximately 30 MHz
(or for pulses with rise times less than about 11 ns).
You can choose between a ground lead terminated with an alligator clip and a
lead terminated with a square-pin receptacle.
Low-Inductance Ground Lead
Low-inductance ground leads reduce ground lead inductance. Compared to a
typical six-inch ground lead with an inductance of approximately 140 nH, the
low-inductance tip assembly has an inductance of approximately 32 nH. That
means that your measurements will be relatively free of probe-related high-
frequency degradation up to approximately 250 MHz.
The low-inductance tip has a partially insulated flexible ground pin that allows
you to ground the probe and still have a limited amount of reach with the
probe tip. Because the ground lead simply contacts the ground reference
(instead of clipping onto it) you can move the probe around your device under
test with ease. The assembly is well-suited to densely populated circuit
boards and multi-pin connectors.
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Probe Accessories
Probe-Tip-to-Circuit Board Adapters
The probe-tip-to-circuit board adapters let you design minimum inductance
test points into your next circuit board. That adapter provides maximum
performance for the probe, because it virtually eliminates ground inductance
effects.
Instructions for installing the probe tip-to-circuit board adapters are packaged
with the adapters. For the best performance and ease of testing, Tektronix
strongly recommends that you incorporate the probe tip-to-circuit board
adapters (or the probe tip-to-chassis adapters described below) into your next
design.
To use your probe with these adapters, unscrew and remove the ribbed
ferrule. Use the probe tip directly with the adapter.
SMT KlipChipTM
The SMT KlipChip provides hands-free attachment to a physically small
signal or ground source. The low profile of the KlipChip allows you to grasp
surface-mounted devices that the full-size retractable hook tip can not grip.
You can use the KlipChip as a ground attachment, as a signal attachment, or
to attach both to a ground and a signal.
For a ground attachment, use the long ground lead (described on
page 3-100) terminated with a pin receptacle, and connect the termination
to the pin in one of the KlipChip shoulders.
For a signal attachment, use a single-lead adapter (similar to the dual-
lead adapter described on page 3-103), and connect the termination to
the pin in one of the KlipChip shoulders.
For both ground and signal attachment, combine two KlipChips with a
dual-lead adapter, or use a single-lead adapter and a long ground lead.
Optional probe accessories that you can order include the following:
Optional Probe
Accessories
Low-Inductance Spring Tips
The low-inductance spring tips can be used whenever you are measuring
devices with fixed spacings. The spring-tip is ideal for repetitive production
use. Select different length springs to match device spacings on a variety of
components. Because the spring-tip ground lead simply contacts the ground
reference (instead of clipping onto it) you can move the probe around your
device-under-test with ease.
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Probe-Tip-to-Chassis Adapter
The probe-tip-to-chassis adapter makes your test point accessible without
removing instrument covers or panels. It provides an easy-access, low-induc-
tance test point anywhere on your circuit. The probe-tip-to-chassis adapter
has the same low inductance properties as the probe-tip-to-circuit board
adapter described previously.
To use your probe with these adapters, unscrew and remove the ribbed
ferrule.
Compact-to-Miniature Probe Tip Adapter
The compact-to-miniature probe tip adapter allows you to use accessories
that are designed to accept a larger probe tip. These accessories include the
IC protector tip, single- and dual-lead adapters, and others.
To install the adapter, unscrew and remove the ribbed ferrule, and screw the
adapter on in its place. (The IC protector tip discussed below is installed on
the adapter tip when shipped. Remove the protector tip by pulling it off before
using the adapter with other accessories.)
IC Protector Tip
The IC protector tip simplifies probing inline IC packages. The shape of the IC
protector guides the probe tip to the IC pin and prevents accidental shorting of
pins by the probe tip. It is used with the compact-to-miniature probe tip adapt-
er. When using that tip, the spacing (pitch) between leads should be greater
than or equal to 0.100 inches (100 mils).
Because the IC protector tip prevents you from using the low-inductance tips,
you will have to use one of the longer ground leads. For that reason you
should take into account ground lead inductance effects on measurements at
frequencies greater than about 30 MHz.
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Probe Accessories
Dual-Lead Adapter
The dual-lead adapter makes an easy connection to 0.025 diameter connec-
tor pins (see Figure 3-54). One lead connects to a ground reference pin, and
the other to the signal pin. The adapter prevents burring and pin damage that
can result when a retractable hook tip is used on soft pins. A single-lead
adapter is also available. These adapters can also be used with the SMT
KlipChip to provide access to very small signal and ground test points.
Although the dual-lead adapter is an improvement over the long ground leads
in terms of added inductance, measurements at frequencies greater than
30 MHz may require using one of the low-inductance ground leads. Because
of the length of the signal lead, the dual-lead configuration is also more
susceptible to signal crosstalk than other tip configurations.
Figure 3-54: Dual-Lead Adapter
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Probe Cal
This oscilloscope lets you compensate the entire signal path, from probe tip to
digitized signal, to improve the gain and offset accuracy of the probe. By
executing Probe Cal on a channel with its probe installed, you can optimize
the oscilloscope capability to make accurate measurements using that chan-
nel and probe.
Run a Probe Cal anytime you wish to ensure that the measurements you
make are made with the most accuracy possible. You should also run a Probe
Cal if you have changed to a different probe since the last Probe Cal was
performed.
Probe Cal vs. Probe Type
Some types of probes can be gain compensated, some can be offset com-
pensated, and some can be compensated for both. Some probes cannot be
compensated.
If your probe has an attenuation factor of greater than 20X, it cannot be
compensated. If you attempt to compensate such a probe you will get an
error message.
The digitizing oscilloscope cannot compensate probes whose gain and/or
offset errors are too great ( 2% gain and/or 50 mV offset). If these errors
are within specified limits for your probe, you may wish to use another probe.
If they are not within specification, have your probe checked by service
personnel.
NOTE
Probe Cal is not recommended with the P6139A passive probe.
This probe typically has little gain and offset error, and therefore, the
improvement in performance after a Probe Cal is not worth the time
needed to do the Probe Cal. Probe Cal makes significant perfor-
mance improvements when performed with active probes or older
passive probes.
If you are installing an active probe, such as the P6205, there are no prereq-
uisites to performing this procedure. Start at step 1.
Operation
If you are compensating for a passive probe with this procedure you must first
compensate the low frequency response of the probe. First, do steps 1 and 2
below, and then perform the instructions found under Probe Compensation on
page 3-110. Then continue with step 3 of this procedure.
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Probe Cal
1. Install the probe on the input channel on which it is to be used.
2. Power on the digitizing oscilloscope and allow a 20 minute warm-up
before doing this procedure.
3. Press SHIFT UTILITY ➞ System (main) ➞ Cal (pop-up).
4. Look at the status label under Signal Path in the main menu. If the status
does not read Pass, perform a signal path compensation (Signal Path
Compensation, page 3-138), and then continue with this procedure.
5. Press the front-panel button corresponding to the input channel on which
you installed the probe.
6. Press VERTICAL MENU ➞ Cal Probe (main).
Your oscilloscope will detect the type of probe you have installed and
display screen messages and menu choices for compensation of
probe gain, offset, or both (see Figure 3-55). The following steps will
have you run probe gain, offset, or both depending on the probe the
oscilloscope detects.
7. If the message on screen is Probe Offset Compensation rather than
Probe Gain Compensation, skip to step 15.
8. Connect the probe tip to PROBE COMPENSATION SIGNAL; connect
the probe ground lead to PROBE COMPENSATION GND.
9. Press OK Compensate Gain (side).
10. Wait for gain compensation to complete (one to three minutes).
When gain compensation completes, the following actions occur:
The clock icon will disappear.
If offset compensation is required for the probe installed, the Probe
Offset Compensation message will replace the Probe Gain Compen-
sation message.
If gain compensation did not complete successfully, you may get a
“Probe is not connected” message (examine the probe connections to
the digitizing oscilloscope, be sure the probe tip is properly installed in
its retractor, etc., and repeat step 9).
If gain compensation did not complete successfully, you may get the
message “Compensation Error.” This error implies that the probe gain
(2% error) and/or offset (50 mV) is too great to be compensated. You
can substitute another probe and continue. Have your probe checked
by service personnel.
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Probe Cal
Figure 3-55: Probe Cal Menu and Gain Compensation Display
11. If the Probe Offset Compensation message is displayed, continue with
step 15; otherwise, continue with step 12.
12. If the Compensation Error message is displayed, continue with step 13;
otherwise continue with step 18.
13. Press SHIFT UTILITY ➞ System (main) ➞ Diag/Err (pop-up) ➞ Error
Log (main). If there are too many error messages to be seen on screen,
rotate the general purpose knob clockwise to scroll to the last message.
14. Note the compensation error amount. Skip to step 19.
15. Disconnect the probe from any signal you may have connected it to.
Leave the probe installed on its channel.
16. Press OK Compensate Offset (side).
17. Wait for offset compensation to complete (one to three minutes).
When offset compensation completes, the following occurs:
The clock icon will disappear.
If offset compensation did not complete successfully, you may get the
message “Compensation Error.” This error implies that the probe
offset scale (10% error) and/or offset (50 mV) is too great to be
compensated. You can substitute another probe and continue. Have
your probe checked by service personnel. You can also check the
error log by doing steps 13 through 14.
18. After the clock icon is removed, verify the word Initialized changed to
Pass under Cal Probe in the main menu. (See Figure 3-55.)
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Probe Cal
19. If desired, repeat this procedure beginning at step 1 to compensate for
other probe/channel combinations. But before you do so, be sure you
take note of the following requirements:
Remember to first low frequency compensate any passive probe you
connect (see Prerequisites at the beginning of this procedure).
Remember to connect all but simple passive probes to the oscillo-
scope for a twenty minute warm up before running Probe Cal.
The following topic contains information you should consider when using input
channels that have stored a Probe Cal.
Usage
Changing Probes After a Probe Cal
If a Probe Cal has never been performed on an input channel or if its stored
Probe Cal data is erased using the Re-use Probe Calibration Data menu
(discussed later), the oscilloscope displays Initialized status in its vertical
menu. It also displays initialized whenever you remove a probe from an input.
If you execute a successful Probe Cal on an input channel, the oscilloscope
stores the compensation data it derived in non-volatile memory. Therefore,
this data is available when you turn the oscilloscope off and back on, when
you change probes, etc.
When you install a probe or power on the oscilloscope with probes installed,
the oscilloscope tests the probe at each input. Depending on the probe it finds
on each input, it takes one of the following actions:
If the probe has a complex oscilloscope interface (it can convey additional
information, such as a unique identification number), the oscilloscope
determines whether it is the same probe for which data was stored. If it is,
the oscilloscope sets status to pass; if not, it sets the status to Initialized.
If a probe has a simple oscilloscope interface, the oscilloscope can usual-
ly determine if it has a different probe attenuation factor than that stored
for the last Probe Cal. It can also determine if the last Probe Cal was for a
probe with a complex interface. If either is the case, the probe installed is
different from that stored for the last Probe Cal. Therefore, the oscillo-
scope sets the status to Initialized.
If a probe has a simple oscilloscope interface and the probe attenuation
factor is the same as was stored at the last Probe Cal, the oscilloscope
cannot determine whether it is the same probe. Therefore, it displays the
Re-use Probe Calibration data? menu (see Figure 3-56).
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Probe Cal
Figure 3-56: Re-use Probe Calibration Data Menu
If the Re-use Probe Calibration data? menu is displayed, you can choose one
of the following options:
Press OK Use Existing Data (side) to use the Probe Cal data last stored
to compensate the probe.
Press OK Erase Probe Cal Data (side) to erase the Probe Cal data last
stored and use the probe uncompensated.
Press CLEAR MENU on the front panel to retain the Probe Cal data last
stored and use the probe uncompensated.
NOTE
If the Re-use Probe Calibration data menu is displayed, do not
select OK Use Existing Data if the probe currently installed is not
of the same impedance stored for the Probe Cal. For example, if
the last Probe Cal stored for a channel was done with a passive
50 probe installed, do not install a passive 1 M probe and select
OK Use Existing Data if the menu appears. If you do so, most of
any signal you attempt to measure will not be coupled to the input
channel because of the probe to oscilloscope impedance mismatch.
Table 3-6 shows the action the oscilloscope takes based on the probe con-
nected and user operation performed.
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Probe Cal
Table 3-6: Probe Cal Status
Type Probe Connected
2
Probe
Cal’d?
No
User
1
3
4
Action
Simple Interface
Complex Interface
Doesn’t
Matter
Initialized
Initialized
Yes
Yes
Power
off
Initialized
(probe data is retained)
Initialized
(probe data is retained)
Power
on
Can not detect different probe: Display Re-use Cal’d Probe:
Probe Calibration Data menu
Pass
Different probe:
Initialized
Different probe:
Initialized
Yes
Yes
Disconnect Initialized
Probe
Initialized
Connect
Probe
Can not detect different probe: Display Re-use Cal’d Probe:
Probe Calibration Data menu
Pass
Different probe:
Initialized
Different probe:
Initialized
1
2
3
Refers to a channel input that was successfully compensated at the time Probe Cal was last executed for the input channel.
If no probe is connected, the probe status in the vertical main menu is always initialized.
A probe with a simple interface is a probe that can convey very limited information to the oscilloscope. Most passive probes (includ-
ing those shipped with this instrument) have simple interfaces.
4
A probe with a complex interface is a probe that can convey additional information. For instance, it might automatically set the
oscilloscope input channel impedance to match the probe, send the oscilloscope a unique probe identification number, etc. Some
optical probes and most active probes (such as the optional accessory P6205) have complex interfaces.
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Probe Compensation
Passive probes require compensation to ensure maximum distortion-free
input to the digitizing oscilloscope and to avoid high frequency amplitude
errors (see Figure 3-57).
Probe Compensated Correctly
Probe Overcompensated
Probe Undercompensated
Figure 3-57: How Probe Compensation Affects Signals
To compensate your probe:
Operation
1. Connect the probe to the probe compensation signal on the front panel.
2. Press AUTOSET.
NOTE
When you connect an active probe to the oscilloscope (such as the
P6205), the input impedance of the oscilloscope automatically
becomes 50 . If you then connect a high resistance passive probe
(like the P6139A) you need to set the input impedance back to
1 M Step 4 explains how to change the input impedance.
You now need to limit the bandwidth and change the acquisition mode.
3. Press VERTICAL MENU ➞ Bandwidth (main) ➞ 20 MHz (side).
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Probe Compensation
4. If you need to change the input impedance, press Coupling (main). Then
toggle the side menu selection to get the correct impedance.
5. Press SHIFT ACQUIRE MENU ➞ Mode (main) ➞ Hi Res (side).
6. Adjust the probe until you see a perfectly flat top square wave on the
display. Figure 3-58 shows where the adjustment is located.
Figure 3-58: P6139A Probe Adjustment
See Probe Accessories, on page 3-97.
See Probe Selection, on page 3-112.
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Probe Selection
The probes included with your digitizing oscilloscope are useful for a wide
variety of tasks. However, for special measurement situations you sometimes
need different probes. This section helps you select the right probe for the
job.
Once you have decided the type of probe you need, use Table 3-7
(page 3-117) to determine the specific probe compatible with your TDS 600A
Digitizing Oscilloscope. Or use Table 3-8 (page 3-118) if you want to select
the probe by application.
There are five major types of probes: passive, active, current, optical, and
time-to-voltage probes. Most of these types are discussed here; see your
Tektronix Products Catalog for more information.
Passive voltage probes measure voltage. They employ passive circuit compo-
nents such as resistors, capacitors, and inductors. There are three common
classes of passive voltage probes:
Passive Voltage
Probes
General purpose (high input resistance)
Low impedance (Z )
O
High voltage
General Purpose (High Input Resistance) Probes
High input resistance probes are considered “typical” oscilloscope probes.
The P6139A probes included with the digitizing oscilloscope are passive
probes. The high input resistance of passive probes (typically 10 M ) pro-
vides negligible DC loading and makes them a good choice for accurate DC
amplitude measurements.
However, their 8 pF to 12 pF (over 60 pF for 1X) capacitive loading can distort
timing and phase measurements. Use high input resistance passive probes
for measurements involving:
Device characterization (above 15 V, thermal drift applications)
Maximum amplitude sensitivity using 1X high impedance
Large voltage range (between 15 and 500 V)
Qualitative or go/no-go measurements
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Probe Selection
Low Impedance (ZO) Probes
Low impedance probes measure frequency more accurately than general
purpose probes, but they make less accurate amplitude measurements. They
offer a higher bandwidth to cost ratio.
These probes must be terminated in a 50 scope input. Input capacitance is
much lower than high Z passive probes, typically 1 pF, but input resistance is
also lower (500 to 5000 typically). Although that DC loading degrades
amplitude accuracy, the lower input capacitance reduces high frequency
loading to the circuit under test. That makes Z probes ideal for timing and
O
phase measurements when amplitude accuracy is not a major concern.
Z probes are useful for measurements up to 40 V.
O
High Voltage Probes
High voltage probes have attenuation factors in the 100X to 1000X range.
The considerations that apply to other passive probes apply to high voltage
probes with a few exceptions. Since the voltage range on high voltage probes
varies from 1 kV to 20 kV (DC + peak AC), the probe head design is mechan-
ically much larger than for a passive probe. High voltage probes have the
added advantage of lower input capacitance (typically 2-3 pF).
P6009
P6015A
Figure 3-59: The P6009 and P6015A High Voltage Probes
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Probe Selection
Active voltage probes, sometimes called “FET” probes, use active circuit
elements such as transistors. There are three classes of active probes:
Active Voltage
Probes
High speed active
Differential active
Fixtured active
Active voltage measuring probes use active circuit elements in the probe
design to process signals from the circuit under test. All active probes require
a source of power for their operation. Power is obtained either from an exter-
nal power supply or from the oscilloscope itself.
NOTE
When you connect an active probe to the oscilloscope (such as the
P6205), the input impedance of the oscilloscope automatically
becomes 50 . If you then connect a passive probe (like the
P6139A) you need to set the input impedance back to 1 M Verti-
cal Control on page 3-147 explains how to change the input imped-
ance.
High Speed Active Probes
Active probes offer low input capacitance (1 to 2 pF typical) while maintaining
the higher input resistance of passive probes (10 k to 10 M ). Like Z
O
probes, active probes are useful for making accurate timing and phase mea-
surements. However, they do not degrade the amplitude accuracy. Active
probes typically have a dynamic range of
V.
Differential Probes
Differential probes determine the voltage drop between two points in a circuit
under test. Differential probes let you simultaneously measure two points and
to display the difference between the two voltages.
Active differential probes are stand-alone products designed to be used with
50 inputs. The same characteristics that apply to active probes apply to
active differential probes.
Fixtured Active Probes
In some small-geometry or dense circuitry applications, such as surface
mounted devices (SMD), a hand-held probe is too big to be practical. You can
instead use fixtured (or probe card mounted) active probes (or buffered
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Probe Selection
amplifiers) to precisely connect your instrument to your device-under-test.
These probes have the same electrical characteristics as high speed, active
probes but use a smaller mechanical design.
Current probes enable you to directly observe and measure current wave-
forms, which can be very different from voltage signals. Tektronix current
probes are unique in that they can measure from DC to 1 GHz.
Current Probes
Two types of current probes are available: one that measures AC current only
and AC/DC probes that utilize the Hall effect to accurately measure the AC
and DC components of a signal. AC-only current probes use a transformer to
convert AC current flux into a voltage signal to the oscilloscope and have a
frequency response from a few hundred Hertz up to 1 GHz. AC/DC current
probes include Hall effect semiconductor devices and provide frequency
response from DC to 50 MHz.
Use a current probe by clipping its jaws around the wire carrying the current
that you want to measure. (Unlike an ammeter which you must connect in
series with the circuit.) Because current probes are non-invasive, with loading
typically in the milliohm to low range, they are especially useful where low
loading of the circuit is important. Current probes can also make differential
measurements by measuring the results of two opposing currents in two
conductors in the jaws of the probe.
Figure 3-60: A6303 Current Probe Used in the AM 503S Opt. 03
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Probe Selection
Optical probes let you blend the functions of an optical power meter with the
high-speed analog waveform analysis capability of an oscilloscope. You have
the capability of acquiring, displaying, and analyzing optical and electrical
signals simultaneously.
Optical Probes
Applications include measuring the transient optical properties of lasers,
LEDs, electro-optic modulators, and flashlamps. You can also use these
probes in the development, manufacturing, and maintenance of fiber optic
control networks, local area networks (LANs), fiber-based systems based on
the FDDI and SONET standard, optical disk devices, and high-speed fiber
optic communications systems.
NOTE
When you connect any level 2 probe to the oscilloscope, the input
impedance of the oscilloscope automatically becomes 50 . If you
then connect a high input impedance passive probe you need to set
the input impedance back to 1 M Vertical Control, on page 3-147,
explains how to change the input impedance.
The instantaneous time-interval to voltage converter (TVC) continuously
converts consecutive timing measurements to a time-interval versus time
waveform.
Time-to-Voltage
Converter
Timing variations typically appear as left-to-right motion, or jitter, on an oscillo-
scope. Time base or trigger holdoff adjustments may improve display stability,
but they do not show timing dynamics. The TVC untangles the often confus-
ing waveforms and delivers a coherent real-time view.
The TVC adds three measurement functions to the voltage versus time
capability of your oscilloscope: time delay versus time, pulse-width versus
time, and period versus time.
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Probe Selection
Table 3-7 lists TDS 600A compatible probes classified by type.
Probes by Type
Table 3-7: TDS 600A Compatible Probes
Probe Type
Tektronix Model
Description
Passive, high impedance
voltage
P6139A (std.)
P6101A
10X, 500 MHz
1X, 15 MHz
Passive, SMD
P6563AS
P6156
20X, 500 MHz
Passive, low impedance Z
10X, 3.5 GHz, for 50 inputs (1X, 20X, 100X optional)
O
Passive, high voltage
P6009
P6015A
100X,1.5 kV, DC + peak AC
1000X, 20 kV, DC + peak AC
Active, high speed voltage
P6204
DC to 1 GHz FET. DC Offset capability (requires Tektro-
nix 1103 TekProbe Power Supply for offset capability)
Active, high speed voltage
Active, differential voltage
Active, fixtured voltage
P6205
P6046
DC to 750 MHz FET
1X/10X, DC to 100 MHz
A6501
P6501
Opt. 02
Buffer Amplifier, 1 GHz, 1 M 10X
Microprobe with TekProbe Power Cable, 750 MHz,
1 M 10X
Current
AM 503S
AM 503S
Opt. 03
AC/DC. Uses A6302 Current Probe.
AC/DC. Uses A6303 Current Probe.
P6021
P6022
AC. 120 Hz to 60 MHz.
AC. 935 kHz to 120 MHz.
CT-1/CT-2
Designed for permanent or semi-
permanent in-circuit installation
CT-1: 25 kHz to 1 GHz, 50 input
CT-2: 1.2 kHz to 200 MHz, 50 input
Current Transformer for use with
AM 503S and P6021. Peak pulse
1 kA, 0.5 Hz to 20 MHz with AM 503S
CT-4
Logic Word Trigger
P6408
16 channel, one qualifier channel, TTL compatible, +5 V
power supply required
Optical
P6701A
P6703A
P6711
500 to 950 nm, DC to 850 MHz, 1 V/mW
1100 to 1700 nm, DC to 1 GHz, 1 V/mW
500 to 950 nm, DC to 250 MHz, 5 V/mW
1100 to 1700 nm, DC to 300 MHz, 5 V/mW
(Opto-Electronic Converters)
P6713
Time-to-Voltage Converter
TVC 501
Time delay, pulse width and period measurements
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Probe Selection
Another way to classify probes is by application. Different applications de-
mand different probes. Use Table 3-8 to select a probe for your application.
Probes by
Application
Table 3-8: Probes by Application
Telecommuni- Industrial
Consumer/
Computer
Electronics
High Energy
Pulsed Power Regulatory, &
Compliance
Certification,
cations &
High-Speed
Logic
Electronics
Probe Type
Testing
1
1,2
1,2,3
1,2,3
1,2
1,2,3
1,2
Passive, high-impedance P6139A
voltage
P6139A
P6139A
P6139A
P6101A
P6139A
P6101A
1
1,2
1
P6101A
P6101A
P6101A
1
1
1
P6563AS
P6563AS
P6563AS
2,3
2,3
2,3
2,3
2,3
Active, high-speed digital
voltage
P6205
P6205
P6205
P6205
P6205
2,3
P6204
P6204
w/1103 power
2,3
supply
1,2,3
1,2
1,2,3
Low impedance Z
(low capacitance)
P6156
P6156
O
1,2,3
1,2
1,2,3
1,2,3
Passive, high voltage
P6009
P6009
P6009
P6009
P6009
1,2,3
1,2,3
1,2,3
P6015A
P6015A
P6015A
2,3
2,3
2,3
Active, differential voltage P6046
P6046
P6046
2,3
2,3
2,3
2,3
2,3
Current
AM 503S
P6021
AM 503S
AM 503S
P6021
AM 503S
P6021
AM 503S
1,2
1,2
1,2
1,2
1,2
P6021
P6021
1,2
2,3
CT4
CT1/2
CT4
1,2
2,3
2,3
2,3
Fixtured
A6501
P6501
A6501
2,3
P6501
2,3
Logic Word Trigger
Optical
P6408
P6408
2,3
2,3
2,3
2,3
P6701A
P6703A
P6711
P6713
P6701A
P6701A
P6703A
P6711
P6713
2,3
2,3
P6703A
2,3
2,3
2,3
P6711
2,3
2,3
2,3
P6713
2,3
2,3
2,3
2,3
Time-to-voltage converter TVC 501
TVC 501
TVC 501
TVC 501
1
2
3
Qualitative signal evaluation — use when a great deal of accuracy is not required, such as when making go/no go measurements.
Functional testing — use when the device under test is being compared to some standard.
Quantitative Signal Evaluation — use when detailed evaluation is needed.
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Pulse Triggering
Pulse triggering can be very useful. For example, you might be testing a
product with a glitch in the power supply. The glitch appears once a day. So
instead of sitting by and waiting for it to appear, you can use pulse triggering
to automatically capture your data.
There are three classes of pulse triggering: glitch, runt, and width.
A glitch trigger occurs when the trigger source detects a pulse narrower
(or wider) in width than some specified time. It can trigger on glitches of
either polarity. Or you can set the glitch trigger to reject glitches of either
polarity.
A runt trigger occurs when the trigger source detects a short pulse that
crosses one threshold but fails to cross a second threshold before re-
crossing the first. You can set the oscilloscope to detect positive or nega-
tive runt pulses.
A width trigger occurs when the trigger source detects a pulse that is
inside or, optionally, outside some specified time range (defined by the
upper limit and lower limit). The oscilloscope can trigger on positive or
negative width pulses.
Figure 3-61 shows the pulse trigger readouts. Table 3-9, on page 3-120,
describes the choices for pulse triggers.
Trigger Class = Runt
Figure 3-61: Pulse Trigger Readouts
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Pulse Triggering
Table 3-9: Pulse Trigger Definitions
Definition
Name
Glitch positive
Glitch negative
Glitch either
Triggering occurs if the oscilloscope detects
positive spike widths less than the specified
glitch time.
Triggering occurs if the oscilloscope detects
negative spike widths less than the specified
glitch time.
Triggering occurs if the oscilloscope detects
positive or negative widths less than the speci-
fied glitch time.
Runt positive
Triggering occurs if the oscilloscope detects a
positive pulse that crosses one threshold going
positive but fails to cross a second threshold
before recrossing the first going negative.
Runt negative
Triggering occurs if the oscilloscope detects a
negative going pulse that crosses one thresh-
old going negative but fails to cross a second
threshold before recrossing the first going posi-
tive.
Runt either
Triggering occurs if the oscilloscope detects a
positive or negative going pulse that crosses
one threshold but fails to cross a second
threshold before recrossing the first.
Width positive
Width negative
Triggering occurs if the oscilloscope finds a
positive pulse with a width between, or option-
ally outside, the user-specified lower and upper
time limits.
Triggering occurs if the oscilloscope finds a
negative pulse with a width between, or option-
ally outside, the user-specified lower and upper
time limits.
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Pulse Triggering
The pulse trigger menus let you define the pulse source, select the mode
(auto or normal), and adjust the holdoff. To bring up the Pulse Trigger menu:
Operations Common
to Glitch, Runt, and
Width
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Glitch, Runt, or Width (pop-up) (see Figure 3-62).
Figure 3-62: Main Trigger Menu — Glitch Class
Source
Use this main menu item to specify which channel becomes the pulse trigger
source.
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Source (main) ➞ Ch1, Ch2, Ch3 (Ax1 on the TDS 620A & 524A), or Ch4
(Ax2 on the TDS 620A & 524A) (side).
Mode & Holdoff
To change the holdoff time and select the trigger mode:
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Mode and
Holdoff (main) ➞ Auto or Normal (side).
In Auto mode the oscilloscope acquires a waveform after a specific
time has elapsed even if a trigger does not occur. The amount of time
the oscilloscope waits depends on the time base setting.
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Pulse Triggering
In Normal mode the oscilloscope acquires a waveform only if there is
a valid trigger. (You can force a single acquisition by pressing FORCE
TRIGGER.)
2. To change the holdoff time, press Holdoff (side). Use the general pur-
pose knob or the keypad to enter the value in percent.
When you select the pulse class Glitch, the oscilloscope will trigger on a
pulse narrower (or wider) in width than some specified time.
Glitch Operations
Polarity & Width
This menu item lets you define the glitch in terms of polarity (positive, nega-
tive, or either) and width.
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Polarity
and Width (main) ➞ Positive, Negative, or Either (side).
Glitch Positive looks at positive-going pulses.
Glitch Negative looks at negative-going pulses.
Glitch Either looks at both positive and negative pulses.
2. Press Width (side), and set the glitch width using the general purpose
knob or keypad.
Glitch (Accept or Reject)
To specify whether to trigger on glitches or filter out glitches using the Glitch
main menu item, press TRIGGER MENU ➞ Type (main) ➞ Pulse
(pop-up) ➞ Class (main) ➞ Glitch (pop-up) ➞ Glitch (main) ➞ Accept
Glitch or Reject Glitch (side).
If you choose Accept Glitch, the oscilloscope will trigger only on pulses
narrower than the width you specified. If you select Reject Glitch, it will
trigger only on pulses wider than the specified width.
Level
To set the trigger level with the Level main menu (or the front panel trigger
LEVEL knob), press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Level (main) ➞ Level, Set to TTL, Set to ECL, or Set to 50% (side).
If you select Level, enter a value with the general purpose knob or the
keypad.
If you select Set to TTL, the trigger level is set to the TTL switching
threshold.
If you select Set to ECL, the trigger level is set to the ECL switching
threshold.
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Pulse Triggering
If you select Set to 50%, you cause the digitizing oscilloscope to search
for the point halfway between the peaks of the trigger source signal and
set the trigger level to that point.
When you select the pulse class Runt, the oscilloscope will trigger on a short
pulse that crosses one threshold but fails to cross a second threshold before
recrossing the first. To set up runt triggering:
Runt Operation
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Class (main) ➞ Runt (pop-up) ➞ Source (main) ➞ Ch1, Ch2, Ch3 (Ax1
on the TDS 620A & 524A), or Ch4 (Ax2 on the TDS 620A & 524A) (side).
(See Figure 3-63.)
2. Press Polarity (main) ➞ Positive, Negative, or Either (side).
3. Press Thresholds (main), and set the upper and lower thresholds for
runt detection with the side menu selections and the keypad or the gener-
al purpose knob.
Polarity
Use this menu item to specify the direction of the runt pulse.
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Runt (pop-up) ➞ Polarity (main) ➞ Positive, Negative, or Either (side).
Positive looks for positive-going runt pulses.
Negative looks for negative-going runt pulses.
Either looks for both positive and negative runt pulses.
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Pulse Triggering
Selected Trigger Bar at Upper Threshold
Unselected Trigger Bar at Lower
Threshold
Runt Pulse Crosses First Threshold
Only, Recrosses First Threshold Level,
and Triggers Acquisition
Figure 3-63: Main Trigger Menu—Runt Class
Thresholds
To set the two threshold levels used in detecting a runt pulse:
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Class (main) ➞ Runt (pop-up) ➞ Thresholds (main).
2. Use the general purpose knob or keypad to set the values for the high
and low thresholds.
Hint: To use the Trigger Bar feature to set the threshold levels on the
pulse train, press DISPLAY ➞ Readout Options (main) ➞ Trigger Bar
Style (side) until Long appears in that menu item.
Note the position of the trigger indicator in Figure 3-63. Triggering occurs at
the point the pulse returns over the first (lower) threshold going negative
without crossing the second threshold level (upper). Be aware of the following
considerations when using Runt triggering:
When Positive is set in the Polarity side menu, the lower threshold must
be first crossed going positive, then recrossed going negative without
crossing the upper threshold at all.
When Negative is set in the Polarity side menu, the upper threshold
must be first crossed going negative, then recrossed going positive
without crossing the lower threshold at all.
When Either is set in the Polarity side menu, one threshold must be first
crossed going in either direction, then recrossed going in the opposite
direction without crossing the other threshold at all.
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Pulse Triggering
Regardless of the polarity setting, triggering occurs at the point the runt
pulse recrosses its first threshold.
When you select the pulse class Width, the oscilloscope will trigger on a
pulse narrower (or wider) than some specified range of time (defined by the
upper limit and lower limit).
Width Operation
Polarity
To define whether the pulses are positive or negative:
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Width (pop-up) ➞ Polarity (main) ➞ Positive or Negative (side).
Trig When
This menu item lets you establish the range of widths (in units of time) the
trigger source will search for and whether to trigger on pulses that are outside
this range or ones that fall within the range.
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Class (main) ➞ Width (pop-up) ➞ Trig When (main).
2. Press Within Limits (side) if you want the oscilloscope to trigger on
pulses that fall within the specified range. If you want it to trigger on
pulses that are outside the range, then press Out of Limits (side).
3. To set the range of pulse widths in units of time, press Upper Limit (side)
and Lower Limit (side). Enter the values with the general purpose knob
or keypad. The Upper Limit is the maximum valid pulse width the trigger
source will look for. The Lower Limit is the minimum valid pulse width.
The oscilloscope will always force the Lower Limit to be less than or
equal to the Upper Limit.
Level
To set the trigger level with the Level main menu:
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Width (pop-up) ➞ Level (main) ➞ Level, Set to TTL, Set to ECL, or Set to
50% (side).
See Triggering, on page 2-13.
See Triggering, on page 3-142.
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Remote Communication
You may want to integrate your oscilloscope into a system environment and
remotely control your oscilloscope or exchange measurement or waveform
data with a computer. You can control your oscilloscope remotely via the
IEEE Std 488.2–1987 (GPIB) interface.
GPIB enables data transfers between instruments that support the GPIB
protocols. It provides:
GPIB Protocol
Remote instrument control
Bidirectional data transfer
Device compatibility
Status and event reporting
Besides the base protocols, Tektronix has defined codes and formats for
messages to travel over the GPIB. Each device that follows these codes and
formats, such as the TDS 620A, TDS 640A, TDS 524A, & TDS 644A, sup-
ports standard commands. Use of instruments that support these commands
can greatly simplify development of GPIB systems.
GPIB Interface Requirements
You can connect GPIB networks in many configurations if you follow these
rules:
No more than 15 devices, including the controller, can be on a single bus.
Connect one device load every two meters (about six feet) of cable length
to maintain bus electrical characteristics. (Generally, each instrument
represents one device load on the bus.)
The total cumulative cable length must not exceed 20 meters (about
65 feet).
At least two-thirds of the device loads must be turned on when you use
your network.
There must be only one cable path from each device to each other device
on your network (see Figure 3-64), and you must not create loop configu-
rations.
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Remote Communication
GPIB Device
GPIB Device
GPIB Device
GPIB Device
GPIB Device
GPIB Device
GPIB Device
Figure 3-64: Typical GPIB Network Configuration
Cables — An IEEE Std 488.1–1987 GPIB cable (available from Tektronix,
part number 012–0991–00) is required to connect two GPIB devices.
Connector — A 24-pin GPIB connector is located on the oscilloscope rear
panel. The connector has a D-type shell and conforms to IEEE Std
488.1–1987. You can stack GPIB connectors on top of each other (see
Figure 3-65).
Figure 3-65: Stacking GPIB Connectors
GPIB Parameters
In the Utility menu you need to define two important GPIB parameters: mode
and address. You need to set the mode to talker/listener, talk only, or off the
bus. You also need to specify the primary communication address.
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Remote Communication
To set up remote communications, ensure that your oscilloscope is physically
cabled to the controller and that the oscilloscope parameters are correctly set.
Plug an IEEE Std 488.2–1987 GPIB cable into the GPIB connector on the
oscilloscope rear panel and into the GPIB port on your controller (see Fig-
ure 3-66).
Operation
Rear Panel
Controller
Figure 3-66: Connecting the Digitizing Oscilloscope to a Controller
To set remote communications parameters:
Press SHIFT UTILITY ➞ System (main) ➞ I/O (pop-up).
Port Selection
Now you need to configure the port to match the controller (see Figure 3-67).
Press SHIFT UTILITY ➞ System (main) ➞ I/O (pop-up) ➞ Port (main) ➞
GPIB (pop-up) ➞ Configure (main) ➞ Talk/Listen Address, Hardcopy
(Talk Only), or Off Bus (side)
Choose Talk/Listen Address for normal, controller-based system opera-
tion. Use the general purpose knob or the keypad to define the address.
Use Hardcopy (Talk Only) to use the hardcopy port of your digitizing
oscilloscope. Once the port is configured this way, the oscilloscope will
send the hardcopy data to any listeners on the bus when the HARDCO-
PY button is pressed.
If the port is configured any other way and the HARDCOPY button is
pressed, an error will occur and the digitizing oscilloscope will display a
message saying the selected hardcopy port is currently unavailable.
Use Off Bus to disconnect the digitizing oscilloscope from the bus.
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Remote Communication
GPIB Configuration Menu
Figure 3-67: Utility Menu
See Hardcopy, on page 3-59.
See the TDS Family Digitizing Oscilloscopes Programmer Manual.
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Saving and Recalling Setups
You may want to save and reuse setups for many reasons. For example, after
changing the setting during the course of an experiment, you may want to
quickly return to your original setup. You can save and recall up to ten instru-
ment setups from internal oscilloscope memory. The information is retained
even when you turn the oscilloscope off or unplug it.
To save the current setup of the digitizing oscilloscope:
Operation
1. Press SETUP ➞ Save Current Setup (main).
Before doing step 2 that follows, note that if you choose a setup
location labeled user, you will overwrite the user setup previously
stored there. You can store setups in setup locations labeled factory
without disturbing previously stored setups.
2. To store to a setup internally, choose one of the ten internal storage
locations from the side menu To Setup 1, To Setup 2, ... (see Fig-
ure 3-68). Now the current setup is stored in that location.
Figure 3-68: Save/Recall Setup Menu
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Saving and Recalling Settings
To store a setup to disk (optional on the TDS 620A & TDS 640A), press To
File. Then use the general purpose knob to select the exact file from the
resulting scrollbar list. Finally, press the side-menu Save To Selected File to
complete the operation.
Recalling a Setup
To recall a setup stored internally, press SETUP ➞ Recall Saved Set-
up (main) ➞ (Recall Setup 1, Recall Setup 2 ... (side).
To recall a setup stored on disk (optional on the TDS 620A & TDS 640A),
press From File. Then use the general purpose knob to select the exact file
from the resulting scrollbar list. Only files with .set extensions will be dis-
played. Finally, press the side-menu Recall From Selected File to complete
the operation.
Recalling a setup will not change the menu that is currently displayed. If you
recall a setup that is labeled factory in the side menu, you will recall the
factory setup. (The conventional method for recalling the factory setup is
described below.)
Recalling the Factory Setup
To reset your oscilloscope to the factory defaults:
Press SETUP ➞ Recall Factory Setup (main) ➞ OK Confirm Factory Init
(side).
See Factory Initialization Settings, on page A-25, for a list of the factory
defaults.
Deleting All Setups and Waveforms—Tek Secure
Sometimes you might use the digitizing oscilloscope to acquire waveforms
that are confidential. Furthermore, before returning the oscilloscope to gener-
al usage, you might want to remove all such waveforms and any setups used
to acquire them. (Be sure you want to remove all waveforms and setups,
because once they are removed, you cannot retrieve them.) To use Tek
Secure to remove all reference setups and waveforms (does not affect mass
storage disk):
Press SHIFT UTILITY ➞ System (main) ➞ Config (pop-up) ➞ Tek Secure
Erase Memory (main) ➞ OK Erase Ref & Panel Memory (side).
Executing Tek Secure accomplishes the following tasks:
Replaces all waveforms in reference memories with zero sample values.
Replaces the current front panel setup and all setups stored in setup
memory with the factory setup.
Calculates the checksums of all waveform memory and setup memory
locations to verify successful completion of setup and waveform erasure.
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Saving and Recalling Setups
If the checksum calculation is unsuccessful, displays a warning message;
if the checksum calculation is successful, displays a confirmation mes-
sage.
Running File Utilities
To run file utilities (optional on the TDS 620A & TDS 640A), see the File
System article on page 3-55.
See Tutorial Example 4: Saving Setups, on page 1-23.
For More
Information
See Appendix D, Factory Initialization Settings, on page A-25.
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Saving and Recalling Waveforms
You can store a waveform in any of the four internal reference memories of
the digitizing oscilloscope. That information is retained even when you turn
the oscilloscope off or unplug it. You can save any combination of different
size waveform records.
The digitizing oscilloscope can display up to 11 waveforms at one time. That
includes waveforms from the four input channels, four reference waveforms,
and three math waveforms.
You will find saving waveforms useful when working with many waveforms
and channels. If you have more waveforms than you can display, you can
save one of the waveforms and then stop acquiring it. That lets you display
another waveform without forcing you to loose the first one.
To save a waveform, do the following steps:
Operation
1. Select the channel that has the waveform you want to save.
Before doing step 2 that follows, note that if you choose a reference
memory location labeled active (see Figure 3-69), you will overwrite
the waveform that was previously stored there. You can store wave-
forms in reference locations labeled empty without disturbing pre-
viously stored waveforms.
2. To store a waveform internally, press save/recall WAVEFORM ➞ Save
Waveform (main) ➞ Ref1, Ref2, Ref3, Ref4, or File (side).
To store a waveform to disk (optional on the TDS 620A & TDS 640A),
press To File. Then use the general purpose knob to select the exact file
from the resulting scrollbar list. Finally, press the side-menu Save To
Selected File to complete the operation.
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Saving and Recalling Waveforms
Figure 3-69: Save Waveform Menu
Deleting Waveforms
You can choose the Delete Refs main menu item and then select the refer-
ences you no longer need from the side menu (Delete Ref1, Delete Ref2,
Delete Ref3, Delete Ref4, or Delete All Refs).
Deleting All Waveforms and Setups
You can remove all stored reference waveforms and setups using the feature
called Tek Secure. It is described under Saving and Recalling Setups. See
“Deleting All Setups and Waveforms” on page 3-131.
Displaying a Saved Waveform
To display a waveform in internal reference memory:
Press MORE ➞ Ref1, Ref2, Ref3, or Ref4 (main).
Note that in Figure 3-70, the main menu items Ref2, Ref3, and Ref4 appear
shaded while Ref1 does not. References that are empty appear shaded in the
More main menu.
Recalling a Waveform From Disk
To recall a waveform from disk (optional on the TDS 620A & TDS 640A) to an
internal reference memory, press save/recall WAVEFORM ➞ Recall Wfm To
Ref. Then use the general purpose knob to select the exact file from the
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Saving and Recalling Waveforms
resulting scrollbar list. Only files with .WFM extensions are displayed. Finally,
press from the side-menu To Ref1, To Ref2, To Ref3, or To Ref4 choices to
complete the operation.
Figure 3-70: More Menu
Autosave (TDS 640A and 644A only)
To use autosave, press
Autosave (main) ➞ Autosave Single Seq ON (side).
Also turn on Single Acquisition Sequence in the Acquire menu
(see page 3-7).
To disable this feature, simply press
Autosave (main) ➞ Autosave Single Seq OFF (side).
If you enable both autosave and single sequence, the TDS will save all live
channels to reference waveforms at the completion of each single sequence
event. All previous reference waveform data will be erased.
Running File Utilities
To run file utilities (optional on the TDS 620A & TDS 640A), see the File
System article on page 3-55.
See Selecting Channels, on page 3-136.
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Selecting Channels
The selected channel is the channel that the digitizing oscilloscope applies all
waveform-specific activities to (such as measurements or vertical scale and
position).
The channel readout shows the selected channel in inverse video in the lower
left corner of the display. The channel reference indicator for the selected
channel appears along the left side of the display. See Figure 3-71.
Channel Readout
and Reference
Indicator
Channel Reference
Indicator
Channel Readout
Figure 3-71: The Channel Readout
Selecting channels on the TDS 600A series oscilloscopes is straightforward
and easy.
Channel Selection
Buttons
The channel selection buttons are on the right of the display and are labeled
CH 1, CH 2, CH 3 (AUX 1 on the TDS 620A & TDS 524A), CH 4 (AUX 2 on
the TDS 620A & TDS 524A), and MORE. They determine which channel is
selected. The MORE button allows you to select internally stored Math and
Ref waveforms for display and manipulation.
The selected channel is indicated by the lighted LED above each button.
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Selecting Channels
To selecting a channel:
Operation
Pressing CH 1, CH 2, CH 3 (AUX 1 on the TDS 620A & TDS 524A), or CH 4
(AUX 2 on the TDS 620A & TDS 524A) turns the channel on if it is not al-
ready on.
You do not use the channel selection buttons when triggering. Instead you
select the trigger source in the Main Trigger menu or Delayed Trigger menu.
Removing Waveforms From the Display
The WAVEFORM OFF button turns OFF the display of the selected channel
waveform. It will also remove from the display any automated measurements
being made on that waveform.
When you turn off a waveform, the digitizing oscilloscope automatically se-
lects the next highest priority waveform. Figure 3-72 shows how the oscillo-
scope prioritizes waveforms.
1. CH1
2. CH2
3. CH3 (AUX 1 on the TDS 620A & TDS 524A)
4. CH4 (AUX 2 on the TDS 620A & TDS 524A)
5. MATH1
6. MATH2
7. MATH3
8. REF1
9. REF2
10. REF3
11. REF4
Figure 3-72: Waveform Selection Priority
If you are turning off more than one waveform and you start by turning off a
channel waveform, all channels will be turned off before going to the MORE
waveforms. If you start by turning off the MORE waveforms, all the MORE
waveforms will be turned off before going to the channel waveforms.
If you turn off a channel that is a trigger source, it continues to be the trigger
source even though the waveform is not displayed.
See Saving and Recalling Waveforms, on page 3-133.
See Waveform Math, on page 3-159.
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Signal Path Compensation
This oscilloscope lets you compensate the internal signal path used to acquire
the waveforms you acquire and measure. By executing the signal path com-
pensation feature (SPC), you can optimize the oscilloscope capability to make
accurate measurements based on the ambient temperature.
Run an SPC anytime you wish to ensure that the measurements you make
are made with the most accuracy possible. You should also run an SPC if the
temperature has changed more than 5 C since the last SPC was performed.
NOTE
When making measurements at volts/division settings less than or
equal to 5 mV, you should run SPC at least once per week. Failure
to do so may result in the oscilloscope not meeting warranted
performance levels at those volts/div settings. (Warranted charac-
teristics are listed in the Performance Verification manual.)
1. Power on the digitizing oscilloscope and allow a 20 minute warm-up
before doing this procedure.
Operation
2. Disconnect any input signals you may have connected from all four input
channels.
When doing steps 3 and 4, do not turn off the oscilloscope until
signal-path compensation completes. If you interrupt (or lose) power
to the instrument while signal-path compensation is running, a mes-
sage is logged in the oscilloscope error log. If such a case occurs,
rerun signal-path compensation.
3. Press SHIFT UTILITY ➞ System (main) ➞ Cal (pop-up) ➞ Signal
Path (main) ➞ OK Compensate Signal Paths (side).
4. Wait for signal path compensation to complete (one to three minutes).
While it progresses, a “clock” icon (shown at left) is displayed on-screen.
When compensation completes, the status message will be updated to
Pass or Fail in the main menu.
5. Verify the word Pass appears under Signal Path in the main menu. (See
Figure 3-73.)
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Signal Path Compensation
Figure 3-73: Performing a Signal Path Compensation
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Status
The Status menu lets you see information about the oscilloscope state.
To operate the Status menu:
Operation
Press SHIFT STATUS ➞ Status (main) ➞ System, Display, Trigger,
Waveforms, or I/O (side). Note: some oscilloscopes do not have a main
Status menu. On these instruments, press SHIFT STATUS ➞ System,
Display, Trigger, Waveforms, or I/O (side).
System displays information about the Horizontal, Zoom, Acquisition,
Measure, and Hardcopy systems (Figure 3-74). This display also tells you
the firmware version.
Display provides parameter information about the display and color
systems.
Trigger displays parameter information about the triggers.
Waveforms displays information about the various waveforms, including
live, math, and reference.
I/O displays information about the I/O port(s).
Firmware
Version
Figure 3-74: Status Menu — System
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Status
To display the banner (firmware version, options, copyright, and patents):
Banner
NOTE
Some TDS 644A oscilloscopes do not have a Status main menu
with a banner. However, all instruments display the banner briefly at
power-on.
Press SHIFT STATUS ➞ Banner (main) (see Figure 3-75).
Figure 3-75: Banner Display
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Triggering
Triggers determine when the digitizing oscilloscope starts acquiring and
displaying a waveform. The TDS 600A has four types of trigger: edge, logic,
pulse, and, with option 5, video.
Although these triggers are unique, they have some common characteristics
that can be defined and modified using the Trigger menu, buttons, and knob.
This article discusses these common characteristics.
To learn about the general concept of triggering, see Triggering in the Operat-
ing Basics section. To learn more about using specific triggers and using the
delayed trigger system, see For More Information on page 3-145.
The trigger buttons and knob let you quickly adjust the trigger level or force a
trigger (see Figure 3-76).
Trigger Button and
Knobs
Trigger Status
Lights
Figure 3-76: TRIGGER Controls and Status Lights
MAIN LEVEL Knob
The MAIN LEVEL knob lets you manually change the trigger level when
triggering in Edge mode or certain threshold levels when triggering in Logic or
Pulse modes. It adjusts the trigger level (or threshold level) instantaneously
no matter what menu, if any, is displayed.
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Triggering
To Set to 50%
You can quickly obtain an edge or pulse trigger (except for the Runt class) by
pressing SET LEVEL TO 50%. The oscilloscope sets the trigger level to the
halfway point between the peaks of the trigger signal.
You can also set the level to 50% in the Trigger menu under the main menu
item Level if Edge or Pulse (except for Runt class) is selected.
Note that the MAIN LEVEL knob and menu items apply only to the main
trigger level. To modify the delayed trigger level, use the Level item in the
Delayed Trigger menu.
Force Trigger
By pressing the FORCE TRIG front panel button, you can force the oscillo-
scope to immediately start acquiring a waveform record even without a trigger
event. Forcing a trigger is useful when in normal trigger mode and the input
signal is not supplying a valid trigger. By pressing FORCE TRIG, you can
quickly confirm that there is a signal present for the oscilloscope to acquire.
Once that is established, you can determine how to trigger on it (press SET
LEVEL TO 50%, check trigger source setting, etc.).
The oscilloscope recognizes and acts upon FORCE TRIG even when you
press it before the end of pretrigger holdoff. However, the button has no effect
if the acquisition system is stopped.
Single Trigger
If your goal is to act on the next valid trigger event and then stop, press
SHIFT FORCE TRIG. Now you can initiate the single sequence of acquisi-
tions by pressing the RUN/STOP button.
To leave Single Trig mode, press SHIFT ACQUIRE MENU ➞ Stop Af-
ter (main) ➞ RUN/STOP Button Only (side).
See the description under “Stop After” on page 3-7 for further discussion of
single sequence acquisitions.
The digitizing oscilloscope has display readouts and status lights dedicated to
monitoring the trigger circuitry.
Readouts
Trigger Status Lights
There are three status lights in the Trigger control area (Figure 3-76) indicat-
ing the state of the trigger circuitry. The lights are labeled TRIG’D, READY,
and ARM.
When TRIG’D is lighted, it means the digitizing oscilloscope has recog-
nized a valid trigger and is filling the posttrigger portion of the waveform.
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Triggering
When READY is lighted, it means the digitizing oscilloscope can accept a
valid trigger event, and the digitizing oscilloscope is waiting for that event
to occur.
When ARM is lighted, it means the trigger circuitry is filling the pretrigger
portion of the waveform record.
When both TRIG’D and READY are lighted, it means the digitizing oscil-
loscope has recognized a valid main trigger and is waiting for a delayed
trigger. When the digitizing oscilloscope recognizes a delayed trigger, it
will fill in the posttrigger portion of the delayed waveform.
When ARM, TRIG’D, and READY are all off, the digitizer is stopped.
When ARM, TRIG’D, and READY are all lighted, FastFrame is in effect.
No trigger status monitoring is taking place.
Trigger Display Readout
At the bottom of the display, the Trigger readout shows some of the key
trigger parameters (Figure 3-77). The readouts are different for edge, logic
and pulse triggers.
Main Trigger
Source = Ch 1
Main Time Base Time/Div
Main Time Base
Main Trigger Slope =
Rising Edge
Main Trigger
Level
Figure 3-77: Example Trigger Readouts
The record view at the top of the display shows the location of the trigger
signal in the waveform record and with respect to the display (see Fig-
ure 3-78).
Trigger Position and Level Indicators
In addition to the numerical readouts of trigger level, there are also graphic
indicators of trigger position and level which you can optionally display. These
indicators are the trigger point indicator, the long trigger level bar, and the
short trigger level bar. Figure 3-78 shows the trigger point indicator and
short-style trigger level bar.
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Triggering
The trigger point indicator shows position. It can be positioned horizontally off
screen, especially with long record length settings. The trigger level bar
shows only the trigger level. It remains on screen, regardless of the horizontal
position, as long as the channel providing the trigger source is displayed.
Trigger Position Relative to the
Display and Waveform Record
Trigger Point Indicator Indicating
the Trigger Position on the
Waveform Record
Trigger Bar Indicating the Trigger
Level on the Waveform Record
Figure 3-78: Record View, Trigger Position, and Trigger Level Bar Readouts
Both the trigger point indicator and level bar are displayed from the Display
menu. See Display Readout on page 3-30 for more information.
Each trigger type (edge, logic, and pulse) has its own main trigger menu,
which is described in a separate part of this section (see For More Informa-
tion).
Trigger Menu
To select the trigger type, press TRIGGER MENU ➞ Type (main) ➞ Edge,
Logic, or Pulse (pop-up).
See Delay Triggering, on page 3-22.
See Edge Triggering, on page 3-34.
See Logic Triggering, on page 3-78.
See Pulse Triggering, on page 3-119.
See Triggering, on page 2-13.
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Triggering
See the Option 05 Video Trigger Interface Instruction Manual, Tektronix part
number 070–8748–00.
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Vertical Control
You can control the vertical position and scale of the selected waveform using
the vertical menu and knobs.
By changing the vertical scale, you can focus on a particular portion of a
waveform. By adjusting the vertical position, you can move the waveform up
or down on the display. That is particularly useful when you are comparing
two or more waveforms.
Vertical Knobs
To change the vertical scale and position, use the vertical POSITION and
vertical SCALE knobs. The vertical controls only affect the selected wave-
form.
The POSITION knob simply adds screen divisions to the reference point of
the selected waveform. Adding divisions moves the waveform up and sub-
tracting them moves the waveform down. You also can adjust the waveform
position using the offset option in the Vertical menu (discussed later in this
article).
If you want the POSITION knob to move faster, press the SHIFT button.
When the light above the SHIFT button is on and the display says Coarse
Knobs in the upper right corner, the POSITION knob speeds up significantly.
The Vertical readout at the lower part of the display shows each displayed
channel (the selected channel is in inverse video), and its volts/division setting
(see Figure 3-79).
Vertical Readouts
Vertical Menu
The Vertical menu (Figure 3-79) lets you select the coupling, bandwidth, and
offset for the selected waveform. It also lets you numerically change the
position or scale instead of using the vertical knobs.
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Vertical Control
Vertical Readout
Figure 3-79: Vertical Readouts and Channel Menu
Coupling
To choose the type of coupling for attaching the input signal to the vertical
attenuator for the selected channel and to set its input impedance:
Press VERTICAL MENU ➞ Coupling (main) ➞ DC, AC, GND, or (side).
DC coupling shows both the AC and DC components of an input signal.
AC coupling shows only the alternating components of an input signal.
Ground (GND) coupling disconnects the input signal from the acquisition.
Input impedance lets you select either 1 M or 50
impedance.
NOTE
If you select 50 impedance with AC coupling, the digitizing oscillo-
scope will not accurately display frequencies under 200 kHz.
Also, when you connect an active probe to the oscilloscope (such
as the P6205), the input impedance of the oscilloscope automatical-
ly becomes 50 . If you then connect a passive probe (like the
P6139A), you need to set the input impedance back to 1 M
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Vertical Control
Bandwidth
To eliminate the higher frequency components, change the bandwidth of the
selected channel:
Press VERTICAL MENU ➞ Bandwidth (main) ➞ Full, 100 MHz, or 20 MHz
(side).
Fine Scale
Press VERTICAL MENU ➞ Fine Scale (main) to make fine adjustments to
the vertical scale using the general purpose knob or the keypad.
Position
Press VERTICAL MENU ➞ Position (main) to let the general purpose knob
control the vertical position. Press Set to 0 divs (side) if you want to reset the
reference point of the selected waveform to the center of the display.
Offset
Offset lets you subtract DC bias from the waveform, so the oscilloscope can
acquire the exact part of the waveform you are interested in.
Offset is useful when you want to examine a waveform with a DC bias. For
example, you might be trying to look at a small ripple on a power supply
output. It may be a 100 mV ripple on top of a 15 V supply. Using offset, you
can display the ripple and scale it to meet your needs.
To use offset, press VERTICAL MENU ➞ Offset (main). Use the general
purpose knob to control the vertical offset. Press Set to 0 V (side) if you want
to reset the offset to zero.
See Acquisition, on page 2-19.
For More
Information
See Scaling and Positioning Waveforms, on page 2-25.
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Waveform Differentiation
Advanced DSP Math (optional on TDS 620A & TDS 640A), provides wave-
form differentiation that allows you to display a derivative math waveform that
indicates the instantaneous rate of change of the waveform acquired. Such
waveforms are used in the measurement of slew rate of amplifiers and in
educational applications. You can store and display a derivative math wave-
form in a reference memory, then use it as a source for another derivative
waveform. The result is the second derivative of the waveform that was first
differentiated.
The math waveform, derived from the sampled waveform, is computed based
on the following equation:
Description
Where:
X is the source waveform
Y is the derivative math waveform
T is the time between samples
Since the resultant math waveform is a derivative waveform, its vertical scale
is in volts/second (its horizontal scale is in seconds). The source signal is
differentiated over its entire record length; therefore, the math waveform
record length equals that of the source waveform.
To obtain a derivative math waveform:
Operation
1. Connect the waveform to the desired channel input and select that chan-
nel.
2. Adjust the vertical and horizontal scales and trigger the display (or press
AUTOSET).
3. Press MORE ➞ Math1, Math2, or Math3 (main) ➞ Change Math Defi-
nition (side) ➞ Single Wfm Math (main). See Figure 3-21.
4. Press Set Single Source to (side). Repeatedly press the same button
(or use the general purpose knob) until the channel source selected in
step 1 appears in the menu label.
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Waveform Differentation
Derivative Math
Waveform
Source
Waveform
Figure 3-80: Derivative Math Waveform
5. Press Set Function to (side). Repeatedly press the same button (or use
the general purpose knob) until diff appears in the menu label.
6. Press OK Create Math Wfm (side) to display the derivative of the wave-
form you input in step 1.
You should now have your derivative math waveform on screen. Use the
Vertical SCALE and POSITION knobs to size and position your waveform
as you require.
Automated Measurements of a Derivative Waveform
Once you have displayed your derivative math waveform, you can use auto-
mated measurements to make various parameter measurements. Do the
following steps to display automated measurements of the waveform:
1. Be sure MORE is selected in the channel selection buttons and that the
differentiated math waveform is selected in the More main menu.
2. Press MEASURE ➞ Select Measrmnt (main).
3. Select up to four measurements in the side menu (see Figure 3-81).
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Waveform Differentation
Figure 3-81: Peak-Peak Amplitude Measurement of a Derivative
Waveform
Cursor Measurement of a Derivative Waveform
You can also use cursors to measure derivative waveforms. Use the same
procedure as is found under Waveform Integration on page 3-155. When
using that procedure, note that the amplitude measurements on a derivative
waveform will be in volts per second rather than in volt-seconds as is indi-
cated for the integral waveform measured in the procedure.
When creating differentiated math waveforms from live channel waveforms,
consider the following topics.
Usage
Considerations
Offset, Position, and Scale
Note the following tips for obtaining a good display:
You should scale and position the source waveform so it is contained on
screen. (Off screen waveforms may be clipped, resulting in errors in the
derivative waveform).
You can use vertical position and vertical offset to position your source
waveform. The vertical position and vertical offset will not affect your
derivative waveform unless you position the source waveform off screen
so it is clipped.
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Waveform Differentation
When using the vertical scale knob to scale the source waveform, note
that it also scales your derivative waveform.
Because of the method the oscilloscope uses to scale the source waveform
before differentiating that waveform, the derivative math waveform may be
too large vertically to fit on screen — even if the source waveform is only a
few divisions on screen. You can use Zoom to reduce the size of the wave-
form on screen (see Zoom that follows), but if your waveform is clipped
before zooming, it will still be clipped after it is zoomed.
If your math waveform is a narrow differentiated pulse, it may not appear to
be clipped when viewed on screen. You can detect if your derivative math
waveform is clipped by expanding it horizontally using Zoom so you can see
the clipped portion. Also, the automated measurement Pk-Pk will display a
clipping error message if turned on (see Automated Measurements of a
Derivative Waveform on page 3-151).
If your derivative waveform is clipped, try either of the following methods to
eliminate clipping:
Reduce the size of the source waveform on screen. (Select the source
channel and use the vertical SCALE knob.)
Expand the waveform horizontally on screen. (Select the source channel
and increase the horizontal scale using the horizontal SCALE knob.) For
instance, if you display the source waveform illustrated in Figure 3-80 on
page 3-151 so its rising and falling edges are displayed over more hori-
zontal divisions, the amplitude of the corresponding derivative pulse will
decrease.
Whichever method you use, be sure Zoom is off and the zoom factors are
reset (see Zoom below).
Zoom
Once you have your waveform optimally displayed, you can also magnify (or
contract) it vertically and horizontally to inspect any feature. Just be sure the
differentiated waveform is the selected waveform. (Press MORE, then select
the differentiated waveform in the More main menu. Then use the Vertical and
Horizontal SCALE knob to adjust the math waveform size.)
If you wish to see the zoom factor (2X, 5X, etc.), you need to turn zoom on:
press ZOOM ➞ ON (side). The vertical and horizontal zoom factors appear
on screen.
Whether zoom is on or off, you can press Reset Zoom Factors (side) to
return the zoomed derivative waveform to no magnification.
See Waveform Integration, on page 3-154.
See Fast Fourier Transforms, on page 3-38.
See Waveform Math, on page 3-159.
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Waveform Integration
Advanced DSP Math (optional on TDS 620A & TDS 640A), provides wave-
form integration that allows you to display an integral math waveform that is
an integrated version of the acquired waveform. Such waveforms find use in
the following applications:
Measuring of power and energy, such as in switching power supplies
Characterizing mechanical transducers, as when integrating the output of
an accelerometer to obtain velocity
The integral math waveform, derived from the sampled waveform, is com-
puted based on the following equation:
Description
Where:
x(i) is the source waveform
y(n) is a point in the integral math waveform
scale is the output scale factor
T is the time between samples
Since the resultant math waveform is an integral waveform, its vertical scale
is in volt-seconds (its horizontal scale is in seconds). The source signal is
integrated over its entire record length; therefore, the math waveform record
length equals that of the source waveform.
To obtain an integral math waveform:
Operation
1. Connect the waveform to the desired channel input and select that chan-
nel.
2. Adjust the vertical and horizontal scales and trigger the display (or press
AUTOSET).
3. Press MORE ➞ Math1, Math2, or Math3 (main) ➞ Change Math wave-
form definition (side) ➞ Single Wfm Math (main).
4. Press Set Single Source to (side). Repeatedly press the same button
until the channel source selected in step 1 appears in the menu label.
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Waveform Integration
5. Press Set Function to (side). Repeatedly press the same button until
intg appears in the menu label.
6. Press OK Create Math Waveform (side) to turn on the integral math
waveform.
You should now have your integral math waveform on screen. See Figure
3-82. Use the Vertical SCALE and POSITION knobs to size and position
your waveform as you require.
Integral Math
Waveform
Source
Waveform
Figure 3-82: Integral Math Waveform
Cursor Measurements of an Integral Waveform
Once you have displayed your integrated math waveform, use cursors to
measure its voltage over time.
1. Be sure MORE is selected (illuminated) in the channel selection buttons
and that the integrated math waveform is selected in the More main
menu.
2. Press CURSOR ➞ Mode (main) ➞ Independent (side) ➞ Func-
tion (main) ➞ H Bars (side).
3. Use the general purpose knob to align the selected cursor (solid) to the
top (or to any amplitude level you choose).
4. Press SELECT to select the other cursor.
5. Use the general purpose knob to align the selected cursor (to the bottom
(or to any amplitude level you choose).
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Waveform Integration
6. Read the integrated voltage over time between the cursors in volt-
seconds from the : readout. Read the integrated voltage over time
between the selected cursor and the reference indicator of the math
waveform from the @: readout. See Figure 3-83.
Integral Math
Waveform
Source
Waveform
Figure 3-83: H Bars Cursors Measure an Integral Math Waveform
7. Press Function (main) ➞ V Bars (side). Use the general purpose knob
to align one of the two vertical cursors to a point of interest along the
horizontal axis of the waveform.
8. Press SELECT to select the alternate cursor.
9. Align the alternate cursor to another point of interest on the math wave-
form.
10. Read the time difference between the cursors from the : readout. Read
the time difference between the selected cursor and the trigger point for
the source waveform from the @: readout.
11. Press Function (main) ➞ Paired (side).
12. Use the technique just outlined to place the long vertical bar of each
paired cursor to the points along the horizontal axis you are interested in.
13. Read the following values from the cursor readouts:
Read the integrated voltage over time between the Xs of both paired
cursors in volt-seconds from the : readout.
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Waveform Integration
Read the integrated voltage over time between the X of the selected
cursor and the reference indicator of the math waveform from the @:
readout.
Read the time difference between the long vertical bars of the paired
cursors from the : readout.
Automated Measurements of a Integral Waveform
You can also use automated measurements to measure integral math wave-
forms. Use the same procedure as is found under Waveform Differentiation
on page 3-151. When using that procedure, note that your measurements on
an integral waveform will be in volt-seconds rather than in volts per second as
is indicated for the differential waveform measured in the procedure.
When creating integrated math waveforms from live channel waveforms,
consider the following topics.
Usage
Considerations
Offset, Position, and Scale
Note the following requirements for obtaining a good display:
You should scale and position the source waveform so it is contained on
screen. (Off screen waveforms may be clipped, which will result in errors
in the integral waveform).
You can use vertical position and vertical offset to position your source
waveform. The vertical position and vertical offset will not affect your
integral waveform unless you position the source waveform off screen so
it is clipped.
When using the vertical scale knob to scale the source waveform, note
that it also scales your integral waveform.
DC Offset
The source waveforms that you connect to the oscilloscope often have a DC
offset component. The oscilloscope integrates this offset along with the time
varying portions of your waveform. Even a few divisions of offset in the
source waveform may be enough to ensure that the integral waveform satu-
rates (clips), especially with long record lengths.
You may be able to avoid saturating your integral waveform if you choose a
shorter record length. (Press HORIZONTAL MENU ➞ Record
Length (main).) Reducing the sample rate (use the HORIZONTAL SCALE
knob) with the source channel selected might also prevent clipping. You can
also select AC coupling (on TDS models so equipped) in the vertical menu of
the source waveform or otherwise DC filter it before applying it to the oscillo-
scope input.
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Waveform Integration
Zoom
Once you have your waveform optimally displayed, you may magnify (or
reduce) it vertically and horizontally to inspect any feature you desire. Just be
sure the integrated waveform is the selected waveform. (Press MORE, then
select the integrated waveform in the More main menu. Then use the Vertical
and Horizontal SCALE knobs to adjust the math waveform size.)
If you wish to see the zoom factor (2X, 5X, etc.) you need to turn Zoom on:
press ZOOM ➞ On (side). The vertical and horizontal zoom factors appear
on screen.
Whether Zoom is on or off, you can press Reset Zoom Factors (side) to
return the zoomed integral waveform to no magnification.
See Waveform Differentiation, on page 3-150.
See Fast Fourier Transforms, on page 3-38.
See Waveform Math, on page 3-159.
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Waveform Math
You can mathematically manipulate your waveforms. For example, you might
have a waveform clouded by background noise. You can obtain a cleaner
waveform by subtracting the background noise from your original waveform.
This section describes the invert, add, subtract, divide, and multiply waveform
math features. If your oscilloscope is equipped with Advanced DSP Math
(optional on TDS 620A & TDS 640A), see Fast Fourier Transforms on
page 3-38, Waveform Differentiation on page 3-150, and Waveform Integra-
tion on page 3-154.
To perform waveform math, press the MORE button to bring up the More
menu (Figure 3-84). The More menu allows you to display, define, and manip-
ulate three math functions.
Operation
Figure 3-84: More Menu
Math1, Math2, and Math3
1. Press MORE ➞ Math1, Math2, or Math3 (main) to select the waveform
that you want to display or change.
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Waveform Math
NOTE
If your digitizing oscilloscope is equipped with Advanced DSP Math
(optional on TDS 620A & TDS 640A), the menu item FFT will be at
the same brightness as the menu items Single Wfm Math and
Dual Wfm Math; otherwise, FFT will be dimmed. See pages 3-38,
3-150, and 3-154 for information on FFTs and other advanced math
waveforms.
2. Press Average (side) and enter a value with the general purpose knob or
the keypad to take an average of multiple acquisitions. Press No Ex-
tended Processing (side) to perform math operations only on one
acquisition.
3. If desired, turn on or turn off math averaging. To turn on math averaging,
press Average (side) and turn the general purpose knob (or use the
keypad) to enter the number of times to successively average the math
waveform before completing an acquisition. Press No Extended Proces-
sing (side) to turn off math averaging.
4. Press Change Math waveform definition (side) ➞ FFT (if your oscillo-
scope contains Advanced DSP Math), Single Wfm Math, or Dual Wfm
Math (main) to alter the present math waveform definition (see Fig-
ure 3-85).
The single and dual waveform operations are described separately in the
following topics. For descriptions of Advanced DSP Math, see Fast
Fourier Transforms on page 3-38, Waveform Differentiation on
page 3-150, and Waveform Integration on 3-154.
Single Wfm Math
1. Press MORE ➞ Math1, Math2, or Math3 (main) ➞ Change Math wave-
form definition (side) ➞ Single Wfm Math (main). Press Set Function
to (side) to select inv (invert), intg (if your oscilloscope contains Ad-
vanced DSP Math), or diff (if your oscilloscope contains Advanced DSP
Math). Waveform integration (intg) is described on page 3-154, and
waveform differentiation (diff) is described on page 3-150.
2. To define the source waveform, press Set Single Source to (side).
3. When you are ready to perform the function, press OK Create Math Wfm
(side).
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Waveform Math
Figure 3-85: Dual Waveform Math Main and Side Menus
Dual Wfm Math
1. Select the sources with MORE ➞ Math1, Math2, or Math3 (main) ➞
Change Math waveform definition (side) ➞ Dual Wfm Math (main) ➞
Set 1st Source to and Set 2nd Source to (side). Enter the sources by
repeatedly pressing the appropriate channel selection button.
2. To enter the math operator, press Set operator to (side) to cycle through
the choices. Supported operators are +, –, * and /.
3. Press OK Create Math Wfm (side) to perform the function.
NOTE
If you select *, for multiply, in step 2, the cursor feature will measure
amplitude in the units volts squared VV rather than in volts V.
If your oscilloscope is equipped with Advanced DSP Math, you can also
create integrated, differentiated, and Fast Fourier Transform waveforms. See
Fast Fourier Transforms on page 3-38, Waveform Integration on page 3-150,
and Waveform Differentiation on page 3-154.
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Zoom
At times, you may want to expand or compress a waveform on the display
without changing the acquisition parameters. You can do that with the zoom
feature.
When you zoom in on a waveform on the display, you expand a portion of the
waveform. The digitizing oscilloscope may need to show more points for that
portion than it has acquired. If it needs to do this, it interpolates. The instru-
ment can interpolate in either of two ways: linear or sin(x)/x. (The interpolation
methods are described on page 2-21.)
Zoom and
Interpolation
When you zoom, the display redraws the waveforms using the interpolation
method you selected in the Display menu (linear interpolation or sin(x)/x). If
you selected sin(x)/x (the default), it may introduce some overshoot or under-
shoot to the waveform edges. If that happens, change the interpolation meth-
od to linear, following the instructions on page 3-163.
To differentiate between the real and interpolated samples, set the display
style to Intensified Samples.
When you turn on the zoom feature, the vertical and horizontal scale and
vertical position knobs now control the displayed size and position of wave-
forms, allowing them to be expanded and repositioned on screen. They cease
to affect waveform acquisition, but you can alter acquisition by using the
corresponding menu items. Zoom mode does not change the way horizontal
position operates.
Operation
To use zoom, do the following steps:
1. Press ZOOM ➞ ON (side). The ZOOM front-panel button should light up.
2. Choose which waveforms to zoom by repeatedly pressing Horizontal
Lock (side).
None — only the waveform currently selected can be magnified and
positioned horizontally (Figure 3-86).
Live — all channels (including AUX channels for the TDS 524A &
TDS 620A) can be magnified and positioned horizontally at the same
time. (Waveforms displayed from an input channel are live; math and
reference waveforms are not live.)
All — all waveforms displayed (channels, math, and/or reference)
can be magnified and positioned horizontally at the same time.
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Zoom
NOTE
Although zoom must be turned on to control which waveforms zoom
affects, the setting for Horizontal Lock affects which waveforms
the horizontal control positions whether zoom is on or off. The rules
for the three settings are listed in step 2.
Only the selected
waveform (the top one)
changes size.
Figure 3-86: Zoom Mode with Horizontal Lock Set to None
Setting Interpolation
To change the interpolation method used:
Press DISPLAY ➞ Filter (main) ➞ Sin(x)/x Interpolation or Linear Inter-
polation (side).
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Zoom
Reset Zoom
To reset all zoom factors to their defaults (see Table 3-10), press ZOOM ➞
Reset Zoom Factors (side).
Table 3-10: Zoom Defaults
Parameter
Setting
Zoom Vertical Position
Zoom Vertical Gain
Zoom Horizontal Position
Zoom Horizontal Gain
0
1X
Tracking Horizontal Position
1X
Press ZOOM ➞ Off (side) to return to normal oscilloscope (non-zoom) opera-
tion.
See Acquisition, on page 2-19.
For Further
Information
See Display Modes, on page 3-28.
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Appendices
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Appendix A: Options and Accessories
This section describes the various options as well as the standard and option-
al accessories that are available for the TDS 500A Digitizing Oscilloscopes.
The following options are available:
Options
Options A1–A5: International Power Cords
Besides the standard North American, 110 V, 60 Hz power cord, Tektronix
ships any of five alternate power cord configurations with the oscilloscope
when ordered by the customer.
Table A-1: International Power Cords
Option
A1
Power Cord
Universal European — 220 V, 50 Hz
UK — 240 V, 50 Hz
A2
A3
Australian — 240 V, 50 Hz
North American — 240 V, 60 Hz
Switzerland — 220 V, 50 Hz
A4
A5
Option B1: Service Manual
When Option B1 is ordered, Tektronix ships a service manual with the oscillo-
scope.
Option 1K: K420 Scope Cart
With this option, Tektronix ships the K420 Scope Cart. The cart can help you
transport the oscilloscope around many lab environments.
Option 1M: 50,000 Point Record Length
This option provides a maximum record length of 50,000 points per acquisi-
tion (50,000/channel) and nonvolatile RAM storage of up to four 50,000 point
records.
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Appendix A: Options and Accessories
Warranty-Plus Service Options
The following options add to the services available with the standard warranty.
(The standard warranty appears following the title page in this manual.)
Option M2: When Option M2 is ordered, Tektronix provides five years of
warranty/remedial service.
Option M3: When Option M3 is ordered, Tektronix provides five years of
warranty/remedial service and four oscilloscope calibrations.
Option M8: When Option M8 is ordered, Tektronix provides four calibra-
tions and four performance verifications, one of each in the second
through the fifth years of service.
Option 1F: File System (Standard on TDS 524A & TDS 544A)
With this option, Tektronix ships the digitizing oscilloscope with a floppy disk
drive and a variety of features for managing the floppy disk. With the file
system you can save and recall setups, waveforms, and hardcopies on a
floppy disk.
Option 1P: HC100 4 Pen Plotter
With this option, Tektronix ships a four-color plotter designed to make wave-
form plots directly from the digitizing oscilloscope without requiring an external
controller. It handles A4 and US letter size media.
Option 1Q/2Q: TDS Tutorial
With option 1Q (US) and 2Q (Europe), Tektronix ships a TDS tutorial.
Option 1R: Rackmounted Digitizing Oscilloscope
Tektronix ships the digitizing oscilloscope, when ordered with Option 1R,
configured for installation in a 19 inch wide instrument rack. Customers with
instruments not configured for rackmounting can order a rackmount kit
(016–1136–00 for field conversions).
Instructions for rackmounting the digitizing oscilloscope are shipped with the
option 1R.
Option 13: RS-232/Centronics Hardcopy Interface
(Standard on TDS 524A & TDS 544A)
With this option, Tektronix ships the oscilloscope equipped with a RS-232 and
a Centronics interface that can be used to obtain hardcopies of the oscillo-
scope screen.
Appendices
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Appendix A: Options and Accessories
Option 05: Video Trigger
With this option, Tektronix ships the instrument with tools for investigating
events that occur when a video signal generates a horizontal or vertical sync
pulse. It allows you to investigate a range of NTSC, PAL, SECAM, and high
definition TV signals.
Option 2F: Advanced DSP Math
(Standard on TDS 524A & TDS 544A)
With this option, the oscilloscope can compute and display three advanced
math waveforms: integral of a waveform, differential of a waveform, and an
FFT (Fast Fourier Transform) of a waveform.
Option 2P: Phaser 200e Color Printer
With this option, Tektronix ships a Tektronix Phaser 200e, 300 dpi, thermal
transfer, color printer. It handles letter or A4 size Tektronix thermal paper and
transparencies. It can handle laser copy (plain) paper with the ColorCoat
Transfer Roll.
Option 22: Additional Probes — (TDS 520A & TDS 524A
only)
With this option, Tektronix ships two additional probes identical to the two
standard-accessory P6139A probes normally shipped with the instrument.
This provides one probe for each front-panel input.
Option 23: Active Probes
With this option, Tektronix ships two active high speed voltage probes (the
P6205 10X FET).
Option 25: SMD Probes
With this option, Tektronix ships four passive SMD probes (the P6563AS 20X,
500 MHz).
Option 4P: HC220 Bubble Jet Printer
With this option, Tektronix ships a Tektronix HC220, 360 dpi, 83 cps, plain
paper, bubble jet printer.
Option 9C: Certificate of Calibration and Test Data Report
Tektronix ships a Certificate of Calibration which states this instrument meets
or exceeds all warranted specifications and has been calibrated using stan-
dards and instruments whose accuracies are traceable to the National Insti-
tute of Standards and Technology, an accepted value of a natural physical
TDS 520A, 524A, 540A, & 544A User Manual
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Appendix A: Options and Accessories
constant, or a ratio calibration technique. The calibration is in compliance with
US MIL–STD–45662A. This option also includes a test data report for the
instrument.
The following standard accessories are included with the digitizing oscillo-
scope:
Standard
Accessories
Table A-2: Standard Accessories
Accessory
Part Number
070–8710–01
070–8709–02
070–8711–02
070–8712–01
200–3696–00
161–0230–01
P6139A (single unit)
User Manual
Programmer Manual
Reference
Performance Verification
Front Cover
U.S. Power Cord
Probes, TDS 540A & TDS 544A (quantity four),
10X Passive
TDS 520A & TDS 524A (quantity two),
10X Passive
Probe Accessories
These are accessories to the standard probe listed previously (P6139A).
Except for the probe-tip-to-circuit board adapter, they can also be ordered
separately.
Table A-3: Probe Accessories
Accessory
Part Number
013–0107–06
204–1049–00
Retractable Hook Tip
Body Shell, tip cover
Probe-Tip-to-Circuit Board Adapter
(quantity two standard, optionally available in pack-
age of 25 as 131–5031–00)
No customer order-
able part number for
double unit
Six-inch Slip-On Ground Lead
Low Inductance Ground Lead
196–3113–02
195–4240–00
016–0633–00
Marker Rings Set (quantity eighteen rings which in-
cludes two each of nine colors)
Ground Collar
343–1003–01
Appendices
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Appendix A: Options and Accessories
Table A-3: Probe Accessories (Cont.)
Accessory
Part Number
196–3305–00
003–1433–00
206–0364–00
016–0708–00
Six-inch Alligator Clip Ground Lead
Screwdriver: adjustment tool, metal tip
TM
SMT KlipChip
Accessory Pouch
You can also order the following optional accessories:
Optional Accessories
Table A-4: Optional Accessories
Accessory
Part Number
070–8713–01
HC100
Service Manual
Plotter (GPIB and Centronics Standard)
Oscilloscope Cart
K218
Rack Mount Kit (for field conversion)
Oscilloscope Camera
Oscilloscope Camera Adapter
Soft-Sided Carrying Case
Transit Case
016–1136–00
C9
016–1154–00
016–0909–01
016–1135–00
012–0991–01
012–0991–00
GPIB Cable (1 meter)
GPIB Cable (2 meter)
Accessory Probes
The following optional accessory probes are recommended for use with your
digitizing oscilloscope:
P6101A 1X, 15 MHz, Passive probe.
P6156 10X, 3.5 GHz, Passive, low capacitance, (low impedance Z )
O
probe. Provides 100X, when ordered with Option 25.
P6009 Passive, high voltage probe, 100X, 1500 VDC + Peak AC.
P6015A Passive high voltage probe, 1000X, 20 kVDC + Peak AC
(40 kV peak for less than 100 ms).
P6205 750 MHz probe bandwidth. Active (FET) voltage probe.
TDS 520A, 524A, 540A, & 544A User Manual
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Appendix A: Options and Accessories
P6204 Active, high speed digital voltage probe. FET. DC to 1 GHz. DC
offset. 50 input. Use with 1103 TekProbe Power Supply for offset
control.
P6563AS Passive, SMD probe, 20X, 500 MHz
P6046 Active, differential probe, 1X/10X, DC to 100 MHz, 50 input.
A6501 Buffer Amplifier (active fixtured), 1 GHz, 1 M 10X.
P6501 Option 02: Microprobe with TekProbe power cable (active fixtured),
750 MHz, 1 M 10X.
AM 503S — DC/AC Current probe system, AC/DC. Uses A6302 Current
Probe.
AM 503S Option 03: DC/AC Current probe system, AC/DC. Uses A6303
Current Probe.
P6021 AC Current probe. 120 Hz to 60 MHz.
P6022 AC Current probe. 935 kHz to 120 MHz.
CT-1 Current probe — designed for permanent or semi-permanent in-
circuit installation. 25 kHz to 1 GHz, 50 input.
CT-2 Current probe — designed for permanent or semi-permanent in-
circuit installation. 1.2 kHz to 200 MHz, 50 input.
CT-4 Current Transformer — for use with the AM 503S (A6302) and
P6021. Peak pulse 1 kA. 0.5 Hz to 20 MHz with AM 503S (A6302).
P6701A Opto-Electronic Converter, 500 to 950 nm, DC to 850 MHz,
1 V/mW.
P6703A Opto-Electronic Converter, 1100 to 1700 nm, DC to 1 GHz,
1 V/mW.
P6711 Opto-Electronic Converter, 500 to 950 nm, DC to 250 MHz,
5 V/mW.
P6713 Opto-Electronic Converter, 1100 to 1700 nm, DC to 300 MHz,
5 V/mW.
TVC 501 Time-to-voltage converter. Time delay, pulse width and period
measurements.
Probe Accessories
The following optional accessories are recommended for use with the stan-
dard probe listed under Standard Accessories.
Appendices
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Appendix A: Options and Accessories
Table A-5: Probe Accessories
Accessory
Part Number
013–0226–00
013–0227–00
131–4244–00
131–5031–00
003–1433–01
013–0202–02
352–0670–00
196–3113–03
352–0351–00
015–0201–07
015–0201–08
016–0633–00
SMG50
Connector, BNC: 50 , BNC to Probe Tip Adapter
Connector, Probe: Package of 100, compact
Connector, Probe: Package of 25, compact
Screwdriver Adjustment Tool, Package of five
Compact-to-Miniature Probe Tip Adapter
Probe Tip Holder: (holds three tips)
Three-inch Slip-On Ground Lead
Probe Holder: Black ABS
IC Protector Tip, Package of 10
IC Protector Tip, Package of 100
Marker Ring Set: Two each of nine colors
TM
SMT KlipChip : 20 Adapters
Low-Inductance Spring-Tips: Two each of five
different springs and insulator
016–1077–00
Bayonet Ground Assembly
Probe Tip-to-Chassis Adapter
NOTE
013–0085–00
131–0258–00
The next four items below can only be used with the Compact-to-
Miniature Probe Tip Adapter.
Dual-Lead Adapter
015–0325–00
013–0084–01
017–0088–00
013–0085–00
BNC-to-Probe Tip Adapter
G.R.-to-Probe Tip Adapter, 50
Bayonet Ground Assembly
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Appendix A: Options and Accessories
Accessory Software
The following optional accessories are Tektronix software products recom-
mended for use with your digitizing oscilloscope:
Table A-6: Accessory Software
Software
Part Number
S45F030
EZ-Test Program Generator
Wavewriter: AWG and waveform creation
TekTMS: Test management system
LabWindows
S3FT400
S3FT001
S3FG910
Warranty Information
Check for the full warranty statements for this product, the probes, and the
products listed above on the first page after the title page of each product
manual.
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Appendix B: Algorithms
TDS 600A Digitizing Oscilloscopes can take 25 automatic measurements. By
knowing how they make these calculations, you may better understand how
to use your TDS 600A and how to interpret your results.
TDS 600A Digitizing Oscilloscopes use a variety of variables in their calcula-
tions. These include:
Measurement
Variables
High, Low
is the value used as the 100% level in measurements such as fall time
and rise time. For example, if you request the 10% to 90% rise time, then the
oscilloscope will calculate 10% and 90% as percentages with
ing 100%.
represent-
is the value used as the 0% level in measurements such as fall time and
rise time.
The exact meaning of
and
depends on which of two calculation
methods you choose from the High-Low Setup item of the Measure menu.
These are Min-max and Histogram.
Min-Max Method — defines the 0% and the 100% waveform levels as the
lowest amplitude (most negative) and the highest amplitude (most positive)
samples. The min-max method is useful for measuring frequency, width, and
period for many types of signals. Min-max is sensitive to waveform ringing
and spikes, however, and does not always measure accurately rise time, fall
time, overshoot, and undershoot.
The min-max method calculates the High and Low values as follows:
=
and
=
Histogram Method — attempts to find the highest density of points above
and below the waveform midpoint. It attempts to ignore ringing and spikes
when determining the 0% and 100% levels. This method works well when
measuring square waves and pulse waveforms.
The oscilloscope calculates the histogram-based
follows:
and
values as
1. It makes a histogram of the record with one bin for each digitizing level
(256 total).
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Appendix B: Algorithms
2. It splits the histogram into two sections at the halfway point between
and (also called ).
3. The level with the most points in the upper histogram is the
and the level with the most points in the lower histogram is the
value,
value.
(Choose the levels where the histograms peak for
and
)
If gives the largest peak value within the upper or lower histogram,
then return the value for both and (this is probably a very
low amplitude waveform).
If more than one histogram level (bin) has the maximum value, choose
the bin farthest from
.
This algorithm does not work well for two-level waveforms with greater than
about 100% overshoot.
HighRef, MidRef, LowRef, Mid2Ref
The user sets the various reference levels, through the Reference Level
selection of the Measure menu. They include:
HighRef — the waveform high reference level. Used in fall time and rise time
calculations. Typically set to 90%. You can set it from 0% to 100% or to a
voltage level.
MidRef — the waveform middle reference level. Typically set to 50%. You
can set it from 0% to 100% or to a voltage level.
LowRef — the waveform low reference level. Used in fall and rise time
calculations. Typically set to 10%. You can set it from 0% to 100% or to a
voltage level.
Mid2Ref — the middle reference level for a second waveform (or the second
middle reference of the same waveform). Used in delay time calculations.
Typically set to 50%. You can set it from 0% to 100% or to a voltage level.
Other Variables
The oscilloscope also measures several values itself that it uses to help
calculate measurements.
RecordLength — is the number of data points in the time base. You set it
with the Horizontal menu Record Length item.
Start — is the location of the start of the measurement zone (X-value). It is
0.0 samples unless you are making a gated measurement. When you use
gated measurements, it is the location of the left vertical cursor.
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Appendix B: Algorithms
End — is the location of the end of the measurement zone (X-value). It is
(
– 1.0) samples unless you are making a gated measurement.
When you use gated measurements, it is the location of the right vertical
cursor.
Hysteresis — The hysteresis band is 10% of the waveform amplitude. It is
used in
,
, and
calculations.
For example, once a crossing has been measured in a negative direction, the
waveform data must fall below 10% of the amplitude from the point
before the measurement system is armed and ready for a positive crossing.
Similarly, after a positive crossing, waveform data must go above 10%
of the amplitude before a negative crossing can be measured. Hysteresis is
useful when you are measuring noisy signals, because it allows the digitizing
oscilloscope to ignore minor fluctuations in the signal.
MCross Calculations
MCross1, MCross2, and MCross3 — refer to the first, second, and third
cross times, respectively. See Figure A-1.
The polarity of the crossings does not matter for these variables, but the
crossings alternate in polarity; that is,
could be a positive or negative
crossing, but if
crossing.
is a positive crossing, will be a negative
The oscilloscope calculates these values as follows:
1. Find the first
This is
in the waveform record or the gated region.
.
2. Continuing from
, find the next
in the waveform
. This is
record (or the gated region) of the opposite polarity of
.
3. Continuing from
, find the next
in the waveform
. This is
record (or the gated region) of the same polarity as
.
MCross1Polarity — is the polarity of first crossing (no default). It can be
rising or falling.
StartCycle — is the starting time for cycle measurements. It is a floating-
point number with values between 0.0 and (
– 1.0), inclusive.
=
EndCycle — is the ending time for cycle measurements. It is a floating-point
number with values between 0.0 and (
– 1.0), inclusive.
=
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Appendix B: Algorithms
MCross1
MCross3
(StartCycle)
(EndCycle)
MCross2
MidRef + (Hysteresis x Amplitude)
MidRef
MidRef – (Hysteresis x Amplitude)
Figure A-1: MCross Calculations
Waveform[<0.0 ... RecordLength–1.0>] — holds the acquired data.
TPOS — is the location of the sample just before the trigger point (the time
reference zero sample). In other terms, it contains the domain reference
location. This location is where time = 0.
TSOFF — is the offset between
and the actual trigger point. In other
words, it is the trigger sample offset. Values range between 0.0 and 1.0
samples. This value is determined by the instrument when it receives a
trigger. The actual zero reference (trigger) location in the measurement record
is at (
+
).
The automated measurements are defined and calculated as follows.
Measurement
Algorithms
Amplitude
=
–
Area
The arithmetic area for one waveform. Remember that one waveform is not
necessarily equal to one cycle. For cyclical data you may prefer to use the
cycle area rather than the arithmetic area.
if
=
then return the (interpolated) value at
.
Otherwise,
=
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Appendix B: Algorithms
For details of the integration algorithm, see page A-19.
Cycle Area
Amplitude (voltage) measurement. The area over one waveform cycle. For
non-cyclical data, you might prefer to use the Area measurement.
If
=
then return the (interpolated) value at
.
=
For details of the integration algorithm, see page A-19.
Burst Width
Timing measurement. The duration of a burst.
1. Find
on the waveform. This is
.
2. Find the last
(begin the search at
and search toward
). This is
. This could be a different value from
.
3. Compute
=
–
Cycle Mean
Amplitude (voltage) measurement. The mean over one waveform cycle. For
non-cyclical data, you might prefer to use the Mean measurement.
If
=
then return the (interpolated) value at
.
=
For details of the integration algorithm, see page A-19.
Cycle RMS
The true Root Mean Square voltage over one cycle.
If
=
then
=
.
Otherwise,
=
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Appendix B: Algorithms
For details of the integration algorithm, see page A-19.
Delay
Timing measurement. The amount of time between the
and
crossings of two different traces, or two different places on the same trace.
Delay measurements are actually a group of measurements. To get a specific
delay measurement, you must specify the target and reference crossing
polarities and the reference search direction.
= the time from one
crossing on the source waveform to the
crossing on the second waveform.
Delay is not available in the Snapshot display.
Fall Time
Timing measurement. The time taken for the falling edge of a pulse to drop
from a
value (default = 90%) to a
value (default = 10%).
Figure A-2 shows a falling edge with the two crossings necessary to calculate
a Fall measurement.
1. Searching from
zone greater than
to
, find the first sample in the measurement
.
2. From this sample, continue the search to find the first (negative) crossing
of . The time of this crossing is . (Use linear interpolation if
necessary.)
3. From
, continue the search, looking for a crossing of
. Update
crossing
if subsequent
is found, it becomes
crossings are found. When a
. (Use linear interpolation if necessary.)
4.
=
–
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Appendix B: Algorithms
Fall
Time
THF TL
F
High
HighRef
LowRe
f
Lo
w
Figure A-2: Fall Time
Frequency
Timing measurement. The reciprocal of the period. Measured in Hertz (Hz)
where 1 Hz = 1 cycle per second.
If
= 0 or is otherwise bad, return an error.
= 1/
High
100% (highest) voltage reference value. (See “High, Low” earlier in this
section)
Using the min-max measurement technique:
=
Low
0% (lowest) voltage reference value calculated. (See “High, Low” earlier in
this section)
Using the min-max measurement technique:
=
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Appendix B: Algorithms
Maximum
Amplitude (voltage) measurement. The maximum voltage. Typically the most
positive peak voltage.
Examine all
samples from
to
inclusive, and set
equal to the greatest magnitude
value found.
Mean
The arithmetic mean for one waveform. Remember that one waveform is not
necessarily equal to one cycle. For cyclical data you may prefer to use the
cycle mean rather than the arithmetic mean.
If
=
then return the (interpolated) value at
.
Otherwise,
=
For details of the integration algorithm, see page A-19.
Minimum
Amplitude (voltage) measurement. The minimum amplitude. Typically the
most negative peak voltage.
Examine all
samples from Start to End inclusive, and set Min
equal to the smallest magnitude Waveform[ ] value found.
Negative Duty Cycle
Timing measurement. The ratio of the negative pulse width to the signal
period expressed as a percentage.
is defined in Negative Width, below.
If
= 0 or undefined then return an error.
=
Negative Overshoot
Amplitude (voltage) measurement.
=
Note that this value should never be negative (unless High or Low are set
out-of-range).
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Appendix B: Algorithms
Negative Width
Timing measurement. The distance (time) between
amplitude points of a negative pulse.
(default = 50%)
If
then
= ‘–’
=
=
–
–
else
Peak to Peak
Amplitude measurement. The absolute difference between the maximum and
minimum amplitude.
=
–
Period
Timing measurement. Time taken for one complete signal cycle. The recipro-
cal of frequency. Measured in seconds.
=
–
Phase
Timing measurement. The amount of phase shift, expressed in degrees of the
target waveform cycle, between the crossings of two different wave-
forms. Waveforms measured should be of the same frequency or one wave-
form should be a harmonic of the other.
Phase is a dual waveform measurement; that is, it is measured from a target
waveform to a reference waveform. To get a specific phase measurement,
you must specify the target and reference sources.
Phase is determined in the following manner:
1. The first
(target) waveform are found.
and third
in the source
2. The period of the target waveform is calculated (see “Period” above).
3. The first in the reference waveform crossing
in the same direction (polarity) as that found for the target
waveform is found.
4. The phase is determined by the following:
=
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If the target waveform leads the reference waveform, phase is positive; if it
lags, negative.
Phase is not available in the Snapshot display.
Positive Duty Cycle
Timing measurement. The ratio of the positive pulse width to the signal peri-
od, expressed as a percentage.
is defined in Positive Width, following.
If
= 0 or undefined then return an error.
=
Positive Overshoot
Amplitude (voltage) measurement.
=
Note that this value should never be negative.
Positive Width
Timing measurement. The distance (time) between
amplitude points of a positive pulse.
(default = 50%)
If
then
= ‘+’
=
=
–
–
else
Rise Time
Timing measurement. Time taken for the leading edge of a pulse to rise from
value (default = 10%) to a value (default = 90%).
a
Figure A-3 shows a rising edge with the two crossings necessary to calculate
a Rise Time measurement.
1. Searching from
zone less than
to
.
, find the first sample in the measurement
2. From this sample, continue the search to find the first (positive) crossing
of
. The time of this crossing is the low rise time or
. (Use
linear interpolation if necessary.)
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Appendix B: Algorithms
3. From
, continue the search, looking for a crossing of
. Update
crossing is
. (Use linear interpolation if
if subsequent
found, it becomes the high rise time or
necessary.)
crossings are found. If a
4.
=
–
Rise Time
TLR THR
High
HighRef
LowRe
f
Lo
w
Figure A-3: Rise Time
RMS:
Amplitude (voltage) measurement. The true Root Mean Square voltage.
If
=
then
= the (interpolated) value at
.
Otherwise,
=
For details of the integration algorithm, see below.
Integration Algorithm
The integration algorithm used by the digitizing oscilloscope is as follows:
is approximated by where:
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Appendix B: Algorithms
W(t) is the sampled waveform
is the continuous function obtained by linear interpolation of W(t)
A and B are numbers between 0.0 and
–1.0
If A and B are integers, then:
where s is the sample interval.
Similarly,
is approximated by
where:
W(t) is the sampled waveform
is the continuous function obtained by linear interpolation of W(t)
A and B are numbers between 0.0 and
–1.0
If A and B are integers, then:
where s is the sample interval.
Time measurements on envelope waveforms must be treated differently from
time measurements on other waveforms, because envelope waveforms
contain so many apparent crossings. Unless otherwise noted, envelope
waveforms use either the minima or the maxima (but not both), determined in
the following manner:
Measurements on
Envelope Waveforms
1. Step through the waveform from
max pair DO NOT straddle
to
until the sample min and
.
2. If the pair >
If all pairs straddle
, use the minima, else use maxima.
, use maxima. See Figure A-4.
The Burst Width measurement always uses both maxima and minima to
determine crossings.
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Appendix B: Algorithms
If some samples in the waveform are missing or off-scale, the measurements
will linearly interpolate between known samples to make an “appropriate”
guess as to the sample value. Missing samples at the ends of the measure-
ment record will be assumed to have the value of the nearest known sample.
Missing or
Out-of-Range
Samples
When samples are out of range, the measurement will give a warning to that
effect (for example, “CLIPPING”) if the measurement could change by ex-
tending the measurement range slightly. The algorithms assume the samples
recover from an overdrive condition instantaneously.
MidRef
Both min and max
samples are above
MidRef, so use
minima.
Both min and max
samples are below
MidRef, so use
maxima.
MidRef
Figure A-4: Choosing Minima or Maxima
to Use for Envelope Measurements
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Appendix B: Algorithms
For example, if
is set directly, then
would not change even if
samples were out of range. However, if
was chosen using the %
choice from the Set Levels in % Units selection of the Measure menu, then
could give a “CLIPPING” warning.
NOTE
When measurements are displayed using Snapshot, out of range
warnings are NOT available. However, if you question the validity of
any measurement in the snapshot display, you can select and
display the measurement individually and then check for a warning
message.
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Appendix C: Packaging for Shipment
If you ship the digitizing oscilloscope, pack it in the original shipping carton
and packing material. If the original packing material is not available, package
the instrument as follows:
1. Obtain a corrugated cardboard shipping carton with inside dimensions at
least 15 cm (6 in) taller, wider, and deeper than the digitizing oscilloscope.
The shipping carton must be constructed of cardboard with 170 kg (375
pound) test strength.
2. If you are shipping the digitizing oscilloscope to a Tektronix field office for
repair, attach a tag to the digitizing oscilloscope showing the instrument
owner and address, the name of the person to contact about the instru-
ment, the instrument type, and the serial number.
3. Wrap the digitizing oscilloscope with polyethylene sheeting or equivalent
material to protect the finish.
4. Cushion the digitizing oscilloscope in the shipping carton by tightly pack-
ing dunnage or urethane foam on all sides between the carton and the
digitizing oscilloscope. Allow 7.5 cm (3 in) on all sides, top, and bottom.
5. Seal the shipping carton with shipping tape or an industrial stapler.
NOTE
Do not ship the digitizing oscilloscope with a disk inside the disk
drive (optional on TDS 620A & TDS 640A). When the disk is inside
the drive, the disk release button sticks out. This makes the button
more prone to damage than otherwise.
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Appendix C: Packaging for Shipment
Appendices
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Appendix D: Factory
Initialization Settings
The factory initialization settings provide you a known state for the digitizing
oscilloscope.
Factory initialization sets values as shown in Table A-7.
Settings
Table A-7: Factory Initialization Defaults
Control
Changed by Factory Init to
Acquire mode
Sample
Acquire repetitive signal
Acquire stop after
Acquire # of averages
Acquire # of envelopes
Channel selection
Cursor H Bar 1 position
ON (Enable ET)
RUN/STOP button only
16
10
Channel 1 on, all others off
10% of graticule height
(–3.2 divs from the center)
Cursor H Bar 2 position
90% of the graticule height
(+3.2 divs from the center)
Cursor V Bar 1 position
Cursor V Bar 2 position
Cursor amplitude units
Cursor mode
10% of the record length
90% of the record length
Base
Independent
Off
Cursor function
Cursor time units
Seconds
No change
DC
Date and time
Delayed edge trigger coupling
Delayed edge trigger level
Delayed edge trigger slope
Delayed edge trigger source
0 V
Rising
Channel 1
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Appendix D: Factory Initialization Settings
Table A-7: Factory Initialization Defaults (Cont.)
Changed by Factory Init to
Control
Delay trigger average #
Delay trigger envelope #
Delay time
16
10
16 ns
2
Delay events,
triggerable after main
Delayed, delay by ...
Delayed, time base mode
Display clock
Delay by Time
Delayed Runs After Main
No Change
Display color – collision contrast
(TDS 644A & TDS 524A)
Off
Display color – map math colors
(TDS 644A & TDS 524A)
Color ‘Math’
Color ‘Ref’
Normal
Display color – map reference colors
(TDS 644A & TDS 524A)
Display color – palette
(TDS 644A & TDS 524A)
Display color – palette colors
(TDS 644A & TDS 524A)
The colors of each palette are re-
set to factory hue, saturation, and
lightness (HLS) values
Display color – persistence palette
(TDS 644A & TDS 524A)
Temperature
Display format
YT
Display graticule type
Full
Display intensity – contrast
(TDS 620A & TDS 640A)
175%
Display intensity – text
TDS 620A & TDS 640A: 60%
TDS 644A & TDS 524A: 100%
Display intensity – waveform
TDS 620A & TDS 640A: 80%
TDS 644A & TDS 524A: 100%
Display intensity – overall
(TDS 620A & TDS 640A)
85%
Display interpolation filter
Display style
Sin(x)/x
Vectors
Short
On
Display trigger bar style
Display trigger “T”
Appendices
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Appendix D: Factory Initialization Settings
Table A-7: Factory Initialization Defaults (Cont.)
Control
Changed by Factory Init to
Display variable persistence
Edge trigger coupling
Edge trigger level
Edge trigger slope
Edge trigger source
GPIB parameters
500 ms
DC
0.0 V
Rising
Channel 1
No change
Hardcopy Format
Layout
Unchanged
Unchanged
Unchanged
Unchanged
Palette
Port
Horizontal – delay trigger position
Horizontal – delay time/division
Horizontal – FastFrame
50%
50 s
Off
Horizontal – FastFrame, frame count
Horizontal – FastFrame, frame length
Horizontal – fit to screen
2
500
Off
Horizontal – main trigger position
Horizontal – position
50%
50%
Horizontal – record length
500 points (10 divs)
500 s
Horizontal – main time/division
Horizontal – time base
Main only
Limit template
Limit
Limit
40 mdiv
40 mdiv
Limit template destination
Limit template source
Limit test sources
Ref1
Ch1
Ch1 compared to Ref1; all others
compared to none.
Limit Testing
Off
Off
Limit Testing – hardcopy if condition
met
Limit Testing – ring bell if condition met Off
Logic pattern trigger Ch4 (Ax2) input X (don’t care)
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Appendix D: Factory Initialization Settings
Table A-7: Factory Initialization Defaults (Cont.)
Changed by Factory Init to
Control
Logic state trigger Ch4 (Ax2) input
Rising edge
Logic trigger input
(pattern and state)
Channel 1 = H (high),
Channels 2 & 3 (Ax1) = X (don’t
care)
Logic trigger pattern time qualification
Lower limit
5 ns
5 ns
Upper limit
Logic trigger threshold (all channels)
(pattern and state)
1.2 V
Logic trigger class
Pattern
AND
Logic trigger logic
(pattern and state)
Logic trigger triggers when ...
(pattern and state)
Goes TRUE
Main trigger holdoff
Main trigger mode
Main trigger type
0%
Auto
Edge
Math1 definition
Ch 1 + Ch 2
Math1 extended processing
Math2 definition
No extended processing
Ch 1 – Ch 2 (FFT of Ch 1 on
instruments with Option 2F Ad-
vanced DSP Math)
Math2 extended processing
Math3 definition
No extended processing
Inv of Ch 1
Math3 extended processing
Measure Delay to
No extended processing
Channel 1 (Ch1)
Measure Delay edges
Measure High-Low Setup
Measure High Ref
Both rising and forward searching
Histogram
90% and 0 V (units)
10% and 0 V (units)
50% and 0 V (units)
50% and 0 V (units)
Positive
Measure Low Ref
Measure Mid Ref
Measure Mid2 Ref
Pulse glitch trigger polarity
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Appendix D: Factory Initialization Settings
Table A-7: Factory Initialization Defaults (Cont.)
Control
Changed by Factory Init to
Pulse runt high threshold
Pulse runt low threshold
Pulse runt trigger polarity
Pulse trigger class
Pulse glitch filter state
Pulse glitch width
1.2 V
0.8 V
Positive
Glitch
On (Accept glitch)
2.0 ns
Pulse trigger level
0.0 V
Pulse trigger source
Channel 1 (Ch1)
(Glitch, runt, and width)
Pulse width trigger when ...
Pulse width upper limit
Pulse width lower limit
Pulse width trigger polarity
Repetitive signal
Within limits
2.0 ns
2.0 ns
Positive
On
RS-232 parameters
No change
No change
No change
R/S button
Full
Saved setups
Saved waveforms
Stop after
Vertical bandwidth (all channels)
Vertical coupling (all channels)
DC
Vertical impedance (termination)
(all channels)
1 M
Vertical offset (all channels)
Vertical position (all channels)
Vertical volts/division (all channels)
Zoom horizontal (all channels)
Zoom horizontal lock
0 V
0 divs.
100 mV/division
1.0X
All
Zoom horizontal position
(all channels)
50% = 0.5 (the middle of the
display)
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Appendix D: Factory Initialization Settings
Table A-7: Factory Initialization Defaults (Cont.)
Changed by Factory Init to
Control
Zoom state
Off
Zoom vertical (all channels)
Zoom vertical position (all channels)
1.0X
0 divisions
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Glossary
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Glossary
AC coupling
A type of signal transmission that blocks the DC component of a
signal but uses the dynamic (AC) component. Useful for observing an
AC signal that is normally riding on a DC signal.
Accuracy
The closeness of the indicated value to the true value.
Acquisition
The process of sampling signals from input channels, digitizing the
samples into data points, and assembling the data points into a
waveform record. The waveform record is stored in memory. The
trigger marks time zero in that process.
Acquisition interval
The time duration of the waveform record divided by the record
length. The digitizing oscilloscope displays one data point for every
acquisition interval.
Active cursor
The cursor that moves when you turn the general purpose knob. It is
represented in the display by a solid line. The @ readout on the
display shows the absolute value of the active cursor.
Aliasing
A false representation of a signal due to insufficient sampling of high
frequencies or fast transitions. A condition that occurs when a digitiz-
ing oscilloscope digitizes at an effective sampling rate that is too slow
to reproduce the input signal. The waveform displayed on the oscillo-
scope may have a lower frequency than the actual input signal.
Amplitude
The High waveform value less the Low waveform value.
AND
A logic (Boolean) function in which the output is true when and only
when all the inputs are true. On the digitizing oscilloscope, that is a
trigger logic pattern and state function.
Area
Measurement of the waveform area taken over the entire waveform
or the gated region. Expressed in volt-seconds. Area above ground is
positive; area below ground is negative.
Attenuation
The degree the amplitude of a signal is reduced when it passes
through an attenuating device such as a probe or attenuator. That is,
the ratio of the input measure to the output measure. For example, a
10X probe will attenuate, or reduce, the input voltage of a signal by a
factor of 10.
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Glossary
Automatic trigger mode
A trigger mode that causes the oscilloscope to automatically acquire
if triggerable events are not detected within a specified time period.
Autoset
A function of the oscilloscope that automatically produces a stable
waveform of usable size. Autoset sets up front-panel controls based
on the characteristics of the active waveform. A successful autoset
will set the volts/div, time/div, and trigger level to produce a coherent
and stable waveform display.
Average acquisition mode
In this mode the oscilloscope acquires and displays a waveform that
is the averaged result of several acquisitions. Averaging reduces the
apparent noise. The oscilloscope acquires data as in the sample
mode and then averages it according to a specified number of aver-
ages.
Bandwidth
The highest frequency signal the oscilloscope can acquire with no
more than 3 dB (× .707) attenuation of the original (reference) signal.
Burst width
A timing measurement of the duration of a burst.
Channel
One type of input used for signal acquisition. The TDS 644A &
TDS 640A have four channels; the TDS 524A & TDS 620A have two
full capability and two limited capability channels.
Channel Reference Indicator
The indicator on the left side of the display that points to the position
around which the waveform contracts or expands when vertical scale
is changed. This position is ground when offset is set to 0 V; other-
wise, it is ground plus offset.
Coupling
The association of two or more circuits or systems in such a way that
power or information can be transferred from one to the other. You
can couple the input signal to the trigger and vertical systems several
different ways.
Cursors
Paired markers that you can use to make measurements between
two waveform locations. The oscilloscope displays the values (ex-
pressed in volts or time) of the position of the active cursor and the
distance between the two cursors.
Cycle area
A measurement of waveform area taken over one cycle. Expressed in
volt-seconds. Area above ground is positive; area below ground is
negative.
Cycle mean
An amplitude (voltage) measurement of the arithmetic mean over one
cycle.
Glossary
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Glossary
Cycle RMS
The true Root Mean Square voltage over one cycle.
DC coupling
A mode that passes both AC and DC signal components to the
circuit. Available for both the trigger system and the vertical system.
Delay measurement
A measurement of the time between the middle reference crossings
of two different waveforms.
Delay time
The time between the trigger event and the acquisition of data.
Digitizing
The process of converting a continuous analog signal such as a
waveform to a set of discrete numbers representing the amplitude of
the signal at specific points in time. Digitizing is composed of two
steps: sampling and quantizing.
Display system
The part of the oscilloscope that shows waveforms, measurements,
menu items, status, and other parameters.
Edge Trigger
Triggering occurs when the oscilloscope detects the source passing
through a specified voltage level in a specified direction (the trigger
slope).
Envelope acquisition mode
A mode in which the oscilloscope acquires and displays a waveform
that shows the variation extremes of several acquisitions.
Equivalent-time sampling (ET)
A sampling mode in which the oscilloscope acquires signals over
many repetitions of the event. The TDS 600A Series Digitizing Oscil-
loscopes use a type of equivalent time sampling called random
equivalent time sampling. It utilizes an internal clock that runs
asynchronously with respect to the input signal and the signal trigger.
The oscilloscope takes samples continuously, independent of the
trigger position, and displays them based on the time difference
between the sample and the trigger. Although the samples are taken
sequentially in time, they are random with respect to the trigger.
Fall time
A measurement of the time it takes for trailing edge of a pulse to fall
from a HighRef value (typically 90%) to a LowRef value (typically
10%) of its amplitude.
Frequency
A timing measurement that is the reciprocal of the period. Measured
in Hertz (Hz) where 1 Hz = 1 cycle per second.
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Glossary
Gated Measurements
A feature that lets you limit automated measurements to a specified
portion of the waveform. You define the area of interest using the
vertical cursors.
General purpose knob
The large front-panel knob with an indentation. You can use it to
change the value of the assigned parameter.
Glitch positive trigger
Triggering occurs if the oscilloscope detects positive spike widths less
than the specified glitch time.
Glitch negative trigger
Triggering occurs if the oscilloscope detects negative spike widths
less than the specified glitch time.
Glitch either trigger
Triggering occurs if the oscilloscope detects either positive or nega-
tive spike widths less than the specified glitch time.
GPIB (General Purpose Interface Bus)
An interconnection bus and protocol that allows you to connect
multiple instruments in a network under the control of a controller.
Also known as IEEE 488 bus. It transfers data with eight parallel data
lines, five control lines, and three handshake lines.
Graticule
A grid on the display screen that creates the horizontal and vertical
axes. You can use it to visually measure waveform parameters.
Ground (GND) coupling
Coupling option that disconnects the input signal from the vertical
system.
Hardcopy
An electronic copy of the display in a format useable by a printer or
plotter.
Hi Res acquisition mode
An acquisition mode in which the digitizing oscilloscope averages all
samples taken during an acquisition interval to create a record point.
That average results in a higher-resolution, lower-bandwidth wave-
form. That mode only works with real-time, non-interpolated sam-
pling.
High
The value used as 100% in automated measurements (whenever
high ref, mid ref, and low ref values are needed as in fall time and rise
time measurements). May be calculated using either the min/max or
the histogram method. With the min/max method (most useful for
general waveforms), it is the maximum value found. With the histo-
gram method (most useful for pulses), it refers to the most common
value found above the mid point. See Appendix B: Algorithms for
details.
Glossary
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Glossary
Holdoff, trigger
A specified amount of time after a trigger signal that elapses before
the trigger circuit will accept another trigger signal. Trigger holdoff
helps ensure a stable display.
Horizontal bar cursors
The two horizontal bars that you position to measure the voltage
parameters of a waveform. The oscilloscope displays the value of the
active (moveable) cursor with respect to ground and the voltage value
between the bars.
Interpolation
The way the digitizing oscilloscope calculates values for record points
when the oscilloscope cannot acquire all the points for a complete
record with a single trigger event. That condition occurs when the
oscilloscope is limited to real time sampling and the time base is set
to a value that exceeds the effective sample rate of the oscilloscope.
The digitizing oscilloscope has two interpolation options: linear or
sin(x)/x interpolation.
Linear interpolation calculates record points in a straight-line fit be-
tween the actual values acquired. Sin(x)/x computes record points in
a curve fit between the actual values acquired. It assumes all the
interpolated points fall in their appropriate point in time on that curve.
Intensity
Display brightness.
Interleaving
The way the digitizing oscilloscope attains high digitizing speeds by
combining the efforts of digitizers of several channels. For example, if
you want to digitize on all channels at one time (four on the
TDS 644A & TDS 640A and two on the TDS 524A & TDS 620A),
each of those channels can digitize at a maximum real-time speed of
250 megasamples per second.
Knob
A rotary control.
Logic state trigger
The oscilloscope checks for defined combinatorial logic conditions on
channels 1, 2, and 3 on a transition of channel 4 that meets the set
slope and threshold conditions. If the conditions of channels 1, 2, and
3 are met then the oscilloscope triggers.
Logic pattern trigger
The oscilloscope triggers depending on the combinatorial logic condi-
tion of channels 1, 2, 3, and 4. Allowable conditions are AND, OR,
NAND, and NOR.
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Glossary
Low
The value used as 0% in automated measurements (whenever high
ref, mid ref, and low ref values are needed as in fall time and rise time
measurements). May be calculated using either the min/max or the
histogram method. With the min/max method (most useful for general
waveforms), it is the minimum value found. With the histogram meth-
od (most useful for pulses), it refers to the most common value found
below the mid point. See Appendix B: Algorithms for details.
Main menu
A group of related controls for a major oscilloscope function that the
oscilloscope displays across the bottom of the screen.
Main menu buttons
Bezel buttons under the main menu display. They allow you to select
items in the main menu.
Maximum
Amplitude (voltage) measurement of the maximum amplitude. Typi-
cally the most positive peak voltage.
Mean
Amplitude (voltage) measurement of the arithmetic mean over the
entire waveform.
Minimum
Amplitude (voltage) measurement of the minimum amplitude. Typical-
ly the most negative peak voltage.
NAND
A logic (Boolean) function in which the output of the AND function is
complemented (true becomes false, and false becomes true). On the
digitizing oscilloscope, that is a trigger logic pattern and state func-
tion.
Negative duty cycle
A timing measurement representing the ratio of the negative pulse
width to the signal period, expressed as a percentage.
Negative overshoot measurement
Amplitude (voltage) measurement.
Negative width
A timing measurement of the distance (time) between two amplitude
points — falling-edge MidRef (default 50%) and rising-edge MidRef
(default 50%) — on a negative pulse.
Normal trigger mode
A mode on which the oscilloscope does not acquire a waveform
record unless a valid trigger event occurs. It waits for a valid trigger
event before acquiring waveform data.
Glossary
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Glossary
NOR
A logic (Boolean) function in which the output of the OR function is
complemented (true becomes false, and false becomes true). On the
digitizing oscilloscope, that is a trigger logic pattern and state func-
tion.
OR
A logic (Boolean) function in which the output is true if any of the
inputs are true. Otherwise the output is false. On the digitizing oscillo-
scope, that is a trigger logic pattern and state function.
Oscilloscope
An instrument for making a graph of two factors. These are typically
voltage versus time.
Peak Detect acquisition mode
A mode in which the oscilloscope saves the minimum and maximum
samples over two adjacent acquisition intervals. For many glitch-free
signals, that mode is indistinguishable from the sample mode. (Peak
detect mode works with real-time, non-interpolation sampling only.)
Peak-to-Peak
Amplitude (voltage) measurement of the absolute difference between
the maximum and minimum amplitude.
Period
A timing measurement of the time covered by one complete signal
cycle. It is the reciprocal of frequency and is measured in seconds.
Phase
A timing measurement between two waveforms of the amount one
leads or lags the other in time. Phase is expressed in degrees, where
360
Wave-
forms measured should be of the same frequency or one waveform
should be a harmonic of the other.
Pixel
A visible point on the display. The oscilloscope display is 640 pixels
wide by 480 pixels high.
Pop-up Menu
A sub-menu of a main menu. Pop-up menus temporarily occupy part
of the waveform display area and are used to present additional
choices associated with the main menu selection. You can cycle
through the options in a pop-up menu by repeatedly pressing the
main menu button underneath the pop-up.
Positive duty cycle
A timing measurement of the ratio of the positive pulse width to the
signal period, expressed as a percentage.
Positive overshoot
Amplitude (voltage) measurement.
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Glossary
Positive width
A timing measurement of the distance (time) between two amplitude
points — rising-edge MidRef (default 50%) and falling-edge MidRef
(default 50%) — on a positive pulse.
Posttrigger
The specified portion of the waveform record that contains data
acquired after the trigger event.
Pretrigger
The specified portion of the waveform record that contains data
acquired before the trigger event.
Probe
An oscilloscope input device.
Quantizing
The process of converting an analog input that has been sampled,
such as a voltage, to a digital value.
Probe compensation
Adjustment that improves low-frequency response of a probe.
Pulse trigger
A trigger mode in which triggering occurs if the oscilloscope finds a
pulse, of the specified polarity, with a width between, or optionally
outside, the user-specified lower and upper time limits.
Real-time sampling
A sampling mode where the digitizing oscilloscope samples fast
enough to completely fill a waveform record from a single trigger
event. Use real-time sampling to capture single-shot or transient
events.
Record length
The specified number of samples in a waveform.
Reference memory
Memory in a oscilloscope used to store waveforms or settings. You
can use that waveform data later for processing. The digitizing oscil-
loscope saves the data even when the oscilloscope is turned off or
unplugged.
Rise time
The time it takes for a leading edge of a pulse to rise from a LowRef
value (typically 10%) to a HighRef value (typically 90%) of its ampli-
tude.
RMS
Amplitude (voltage) measurement of the true Root Mean Square
voltage.
Runt trigger
A mode in which the oscilloscope triggers on a runt. A runt is a pulse
that crosses one threshold but fails to cross a second threshold
before recrossing the first. The crossings detected can be positive,
negative, or either.
Glossary
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Glossary
Sample acquisition mode
The oscilloscope creates a record point by saving the first sample
during each acquisition interval. That is the default mode of the
acquisition.
Sample interval
The time interval between successive samples in a time base. For
real-time digitizers, the sample interval is the reciprocal of the sample
rate. For equivalent-time digitizers, the time interval between succes-
sive samples represents equivalent time, not real time.
Sampling
The process of capturing an analog input, such as a voltage, at a
discrete point in time and holding it constant so that it can be quan-
tized. Two general methods of sampling are: real-time sampling and
equivalent-time sampling.
Select button
A button that changes which of the two cursors is active.
Selected waveform
The waveform on which all measurements are performed, and which
is affected by vertical position and scale adjustments. The light over
one of the channel selector buttons indicates the current selected
waveform.
Side menu
Menu that appears to the right of the display. These selections ex-
pand on main menu selections.
Side menu buttons
Bezel buttons to the right of the side menu display. They allow you to
select items in the side menu.
Slope
The direction at a point on a waveform. You can calculate the direc-
tion by computing the sign of the ratio of change in the vertical quanti-
ty (Y) to the change in the horizontal quantity. The two values are
rising and falling.
Tek Secure
This feature erases all waveform and setup memory locations (setup
memories are replaced with the factory setup). Then it checks each
location to verify erasure. This feature finds use where this digitizing
oscilloscope is used to gather security sensitive data, such as is done
for research or development projects.
Time base
The set of parameters that let you define the time and horizontal axis
attributes of a waveform record. The time base determines when and
how long to acquire record points.
Trigger
An event that marks time zero in the waveform record. It results in
acquisition and display of the waveform.
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Glossary
Trigger level
The vertical level the trigger signal must cross to generate a trigger
(on edge trigger mode).
Vertical bar cursors
The two vertical bars you position to measure the time parameter of a
waveform record. The oscilloscope displays the value of the active
(moveable) cursor with respect to the trigger and the time value
between the bars.
Waveform
The shape or form (visible representation) of a signal.
Waveform interval
The time interval between record points as displayed.
XY format
A display format that compares the voltage level of two waveform
records point by point. It is useful for studying phase relationships
between two waveforms.
YT format
The conventional oscilloscope display format. It shows the voltage of
a waveform record (on the vertical axis) as it varies over time (on the
horizontal axis).
Glossary
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Index
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Index
RUN/STOP, 3-8
Sample, 3-7
Single Acquisition Sequence, 3-8
Stop After, 3-8, 3-76
Stop After Limit Test Condition
Met, 3-76
Template Source, 3-73
V Limit, 3-74
Automatic trigger mode, 2-15, Glossa-
ry-2
Numbers
Autoset, 1-10, 2-28, 3-10–3-11,
Glossary-2
1/seconds (Hz), Cursor menu, 3-21
100 MHz, Vertical menu, 3-149
20 MHz, Vertical menu, 3-149
AUTOSET button, 1-11, 3-10, 3-138
AUX TRIGGER INPUT, BNC, 2-5
Auxiliary trigger, 2-14
ACQUIRE MENU button, 3-7, 3-73
Average acquisition mode, 3-6, 3-72,
Glossary-2
Acquisition, 2-19–2-24, 3-10, Glossa-
ry-1
A
Average mode, Acquire menu, 3-74
Average, Acquire menu, 3-7
Average, More menu, 3-160
Interval, Glossary-1
Modes
AC coupling, 2-16–2-17, Glossary-1
AC line voltage, trigger input, 2-14
AC, Main Trigger menu, 3-35
Average, 3-6, 3-72
Envelope, 3-5, 3-72
Hi Res, 3-5
HiRes, 3-72
Peak detect, 3-3
Sample, 3-3
Accept Glitch, Main Trigger menu,
3-122
B
Readout, 3-6
Accessories, A-1–A-8
Optional, A-5
Active cursor, Glossary-1
Bandwidth, 1-1, 2-23, Glossary-2
Bandwidth, Vertical menu, 3-149
Base, Cursor menu, 3-21
Probes, A-4, A-5–A-8
Software, A-8
Standard, A-4, A-7, A-8
Active voltage probes, 3-114–3-115
active, Saved waveform status, 3-133
Algorithms, A-9–A-22
Accuracy, Glossary-1
Baud Rate, Utility menu, 3-60
Bayonet ground assembly, A-7
Blackman-Harris window, 3-41
BMP, 3-59
Aliasing, 2-27, 3-48, Glossary-1
Amplitude, 3-86, Glossary-1
Amplitude Units, Cursor menu, 3-21
AND, Glossary-1
Acquire menu, 3-7, 3-73
Average, 3-7
Average mode, 3-74
Compare Ch1 to, 3-75
Compare Ch2 to, 3-75
Compare Ch3 to, 3-75
Compare Ch4 to, 3-75
Compare Math1 to, 3-75
Compare Math2 to, 3-75
Compare Math3 to, 3-75
Create Limit Test Template, 3-73
Envelope, 3-7
BMP Color, Hardcopy menu, 3-61
BMP Mono, Hardcopy menu, 3-61
AND, Main Trigger menu, 3-82, 3-85
Applications
BNC
derivative math waveforms, 3-150
FFT math waveforms, 3-38
integral math waveforms, 3-154
AUX TRIGGER INPUT, 2-5
DELAYED TRIGGER OUTPUT,
2-5
Area, 3-86, Glossary-1
Attenuation, Glossary-2
MAIN TRIGGER OUTPUT, 2-5
SIGNAL OUTPUT, 2-5
H Limit, 3-74
Hardcopy if Condition Met, 3-76
Hi Res, 3-7
Bold, Color menu, 3-13
Bubble Jet Printer, HC220, A-3
Burst width, 3-86
Auto, Main Trigger menu, 3-37, 3-82,
3-121
Limit Test, 3-76
Limit Test Condition Met, 3-76
Limit Test Setup, 3-75, 3-76
Limit Test Sources, 3-75
Mode, 3-7
OFF (Real Time Only), 3-7
OK Store Template, 3-74
ON (Enable ET), 3-7
Peak Detect, 3-7
Automated Measurements, Snapshot
of, 1-21
Button
Automated measurements, 1-17,
2-30, 3-86
ACQUIRE MENU, 3-7, 3-73
AUTOSET, 1-11, 2-27, 3-10, 3-138
CLEAR MENU, 1-9, 1-18, 1-19,
2-3, 2-8, 3-95
CURSOR, 2-31, 3-19
of derivative math waveforms,
3-151
(procedure), 3-151
of FFT math waveforms, 3-43
DELAYED TRIG, 2-18, 3-25
Repetitive Signal, 3-7
Ring Bell if Condition Met, 3-76
of integral math waveforms, 3-157
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Index
DISPLAY, 3-12, 3-28
Channel, 3-136–3-137, Glossary-2
Readout, 2-6, 3-136
Color, Color menu, 3-14, 3-15
FORCE TRIG, 3-143
HARDCOPY, 3-55, 3-61, 3-128
HELP, 3-67
HORIZONTAL MENU, 2-18, 3-23
MEASURE, 3-89
MORE, 3-134, 3-136, 3-159
ON/STBY, 1-4, 2-3
Save/Recall SETUP, 1-7, 3-55,
Color, Display menu, 3-12
Reference Indicator, 2-6
Selection buttons, 1-13, 3-136
Trigger input, 2-13–2-18
Compact-to-miniature probe tip
adapter, 3-102, A-7
Compare Ch1 to, Acquire menu,
Channel readout, 2-6
3-75
Channel reference indicator, Glossa-
ry-2
Compare Ch2 to, Acquire menu,
3-75
3-130
Circuit loading, Glossary-2
Compare Ch3 to, Acquire menu,
Save/Recall WAVEFORM, 3-55,
Class, Main Trigger menu, 3-80,
3-75
3-133
3-121, 3-123
SELECT, 2-31, 3-20, Glossary-9
SET LEVEL TO 50%, 3-143
SINGLE TRIG, 3-8, 3-143
STATUS, 3-140
TOGGLE, 3-20
TRIGGER MENU, 3-34, 3-80,
3-121, 3-123, 3-145
UTILITY, 3-60, 3-128
VERTICAL MENU, 1-14
WAVEFORM OFF, 1-16, 3-32,
Compare Ch4 to, Acquire menu,
CLEAR MENU button, 1-9, 1-18,
3-75
1-19, 2-3, 2-8, 3-95
Compare Math1 to, Acquire menu,
Clear Spool, Hardcopy menu, 3-62
3-75
Clipping
Compare Math2 to, Acquire menu,
3-75
derivative math waveforms, 3-152
FFT math waveforms, 3-46
how to avoid, 3-46, 3-152, 3-157
integral math waveforms, 3-157
Compare Math3 to, Acquire menu,
3-75
Compensation, 3-110
3-137
ZOOM, 2-28, 3-162
Collision Contrast, Color menu, 3-16
Configure, Utility menu, 3-60, 3-128
Color, 3-12–3-16
Confirm Delete, File Utilities menu,
Buttons
Color Matches Contents, Color
3-58
CH1, CH2 ..., 3-136
Channel selection, 1-13, 3-136
Main menu, 2-3
menu, 3-15
Connector
Color menu, 3-12
Bold, 3-13
AUX TRIGGER INPUT, 2-5
Centronics, 2-5
Side menu, 2-3
Change Colors, 3-13
Collision Contrast, 3-16
Color, 3-14, 3-15
Color Matches Contents, 3-15
Hardcopy, 3-13
Hue, 3-14
DELAYED TRIGGER OUTPUT,
2-5
GPIB, 2-5, 3-127
MAIN TRIGGER OUTPUT, 2-5
Power, 2-5
C
RS-232, 2-5
Lightness, 3-14
Map Math, 3-14
Map Reference, 3-15
Math, 3-14
Monochrome, 3-13
Normal, 3-13
Options, 3-16
Palette, 3-13
Persistence Palette, 3-13
Ref, 3-15
Reset All Mappings To Factory,
SIGNAL OUTPUT, 2-5
VGA, 2-5
Cables, 3-127, 3-128
Cal Probe, Vertical menu, 3-104
Cart, Oscilloscope, A-1
Contrast, Display menu, 3-29
Conventions, ii
CAUTION
Copy, File Utilities menu, 3-57
statement in manuals, v
statement on equipment, v
Coupling, 1-14
AC, 2-16
Centronics, 2-5
DC, 2-16
Port, 3-61
Ground, Glossary-4
Input Signal, 2-23–2-24
Trigger, 2-16
Certificate of Calibration and Test
Data Report, A-3
3-16
Reset All Palettes To Factory,
CH1, CH2 ... buttons, 3-136
3-16
Coupling, Delayed Trigger menu,
Ch1, Ch2 ..., Delayed Trigger menu,
Reset Current Palette To Factory,
3-26
3-26
3-16
Coupling, Main Trigger menu, 3-35
Reset to Factory Color, 3-14
Restore Colors, 3-16
Saturation, 3-14
Spectral, 3-13
Temperature, 3-13
View Palette, 3-13
Ch1, Ch2 ..., Main Trigger menu,
3-34, 3-81, 3-82, 3-84, 3-121,
3-123
Coupling, Vertical menu, 3-148
Create Directory, File Utilities menu,
3-57
Change Colors, Color menu, 3-13
Change Math waveform definition,
More menu, 3-160
Index
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Index
Create Limit Test Template, Acquire
DC offset, 3-46
procedure for displaying, 3-150
menu, 3-73
for DC correction of FFTs, 3-46
with math waveforms, 3-46, 3-157
procedure for measuring, 3-151,
3-152
record length of, 3-150
Create Measrmnt, Measure Delay
menu, 3-95
DC, Main Trigger menu, 3-35
Deskjet, 3-59
Cross Hair, Display menu, 3-31
Define Inputs, Main Trigger menu,
3-82, 3-84
Deskjet, Hardcopy menu, 3-61
Differential active probes, 3-114
Current probes, 3-115
Define Logic, Main Trigger menu,
Cursor
3-82, 3-85
Horizontal bar, 2-31, 3-17
Measurements, 2-31
Mode, 2-31–2-32
Independent, 2-31–2-32
Tracking, 2-32
Paired, 2-31, 3-17
Vertical bar, 2-31, 3-17
Differentiation
Delay by Events, Delayed Trigger
of a derivative, 3-150
waveform, 3-150
menu, 3-25
Delay by Time, Delayed Trigger
Digitizing, Glossary-3
Digitizing rate, 1-1
menu, 3-25
Delay by, Delayed Trigger menu,
Disk drive, 3-55–3-58
3-25
CURSOR button, 3-19
Display, 2-6, 3-10
Options, 3-28–3-33
Record View, 3-144
System, Glossary-3
Delay measurement, 3-93, Glossary-3
Delay time, Glossary-3
Cursor menu, 3-19, 3-42, 3-155
1/seconds (Hz), 3-21
Amplitude Units, 3-21
Base, 3-21
Delay To, Measure Delay menu, 3-93
Delayed Only, Horizontal menu, 3-23
Delayed Runs After Main, 2-18
Display ‘T’ @ Trigger Point, Display
Function, 3-19, 3-20
H Bars, 3-19, 3-20
Independent, 3-20
IRE (NTSC), 3-21
seconds, 3-21
Time Units, 3-21
menu, 3-30
DISPLAY button, 3-12, 3-12, 3-28
Delayed Runs After Main, Horizontal
menu, 3-23, 3-70
Display menu, 3-12, 3-28
Color, 3-12
Delayed Scale, Horizontal menu,
Contrast, 3-29
Cross Hair, 3-31
Display, 3-28
3-70
Tracking, 3-20
Video Line Number, 3-21
DELAYED TRIG button, 2-18, 3-25
Delayed trigger, 2-18, 3-22–3-27
Display ‘T’ @ Trigger Point, 3-30
Dots, 3-29
Dots style, 3-75
Filter, 3-31
Format, 3-32
Frame, 3-31
Full, 3-31
Graticule, 3-31
Grid, 3-31
Infinite Persistence, 3-29
Intensified Samples, 3-29
Intensity, 3-29
Linear interpolation, 3-31
NTSC, 3-31
Overall, 3-29
PAL, 3-31
Readout, 3-30
Settings, 3-12, 3-28
Sin(x)/x interpolation, 3-31
Style, 3-28
Cursor readout
H-Bars, 3-42, 3-152, 3-156
Paired, 3-152
Paired cursors, 3-43, 3-156
V-Bars, 3-42, 3-152, 3-156
Delayed Trigger menu, 3-25–3-27
Ch1, Ch2 ..., 3-26
Coupling, 3-26
Delay by, 3-25
Delay by Events, 3-25
Delay by Time, 3-25
Falling edge, 3-26
Level, 3-26
Rising edge, 3-26
Set to 50%, 3-27
Set to ECL, 3-26
Set to TTL, 3-26
Slope, 3-26
Cursor Readouts, 3-18
Cursor Speed, 3-21
Cursors, 2-31, 3-17–3-21, Glossary-2
with derivative waveforms, 3-152
with FFT waveforms, 3-42
with integral waveforms, 3-155
Cycle area, 3-86, Glossary-3
Cycle mean, 3-86, Glossary-3
Cycle RMS, 3-86, Glossary-3
Source, 3-26
DELAYED TRIGGER OUTPUT, BNC,
2-5
Delayed Triggerable, 2-18
Delayed Triggerable, Horizontal
Text/Grat, 3-29
Trigger Bar, 3-30
Variable Persistence, 3-29
Vectors, 3-29
Waveform, 3-29
XY, 3-32
D
menu, 3-25, 3-70
Delete Refs, Save/Recall Waveform
menu, 3-134
DANGER, statement on equipment, v
Delete, File Utilities menu, 3-56
Date/Time
On hardcopies, 3-62
To set, 3-62
Derivative math waveform, 3-150
applications, 3-150
YT, 3-32
derivation of, 3-150
DC coupling, 2-16, Glossary-3
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Index
Display, Display menu, 3-28
Display, Status menu, 3-140
Dots, 3-29
File Utilities menu, 3-55
Confirm Delete, 3-58
Copy, 3-57
F
Factory initialization settings,
A-25–A-30
Create Directory, 3-57
Delete, 3-56
File Utilities, 3-55
Format, 3-58
Overwrite Lock, 3-58
Print, 3-57
Rename, 3-56
Dots style, Display menu, 3-75
Dots, Display menu, 3-29
DPU411–II, Hardcopy menu, 3-61
DPU412, Hardcopy menu, 3-61
Dual Wfm Math, More menu, 3-160
Dual-lead adapter, 3-103
factory, Saved setup status, 3-130
Fall time, 3-87, Glossary-4
Falling edge, Delayed Trigger menu,
3-26
Falling edge, Main Trigger menu,
3-36, 3-84
File Utilities, File Utilities menu, 3-55
File Utilities, Save/Recall Setup
Fast Fourier Transforms, description,
3-38
Duty cycle, 1-18, Glossary-6, Glossa-
ry-7
menu, 3-132
File Utilities, Save/Recall Waveform
Fast Fourier Transforms (FFTs),
applications, 3-38
menu, 3-135
Filter, Display menu, 3-31
FastFrame interactions, 3-19, 3-72
Fine Scale, Vertical menu, 3-149
Firmware version, 3-140
E
FastFrame Setup, Horizontal menu,
3-71
Edge trigger, 2-14, 3-34, Glossary-3
Readout, 3-34, 3-79
Fit to screen, Horizontal menu, 3-70
Fixtured active probes, 3-114
FORCE TRIG button, 3-143
Format, Display menu, 3-32
Format, File Utilities menu, 3-58
Format, Hardcopy menu, 3-61
Frame Count, Horizontal menu, 3-71
FastFrame, Horizontal menu, 3-71
FFT frequency domain record, 3-44
defined, 3-44–3-54
Edge, Main Trigger menu, 3-34,
3-145
length of, 3-45
Edges, Measure Delay menu, 3-94
FFT math waveform, 3-38
acquisition mode, 3-47
aliasing, 3-48
Either, Main Trigger menu, 3-122,
3-123
automated measurements of, 3-43
DC correction, 3-46
derivation of, 3-38
displaying phase, 3-40
frequency range, 3-45
frequency resolution, 3-45
interpolation mode, 3-47, 3-48
magnifying, 3-47
phase display, setup consider-
ations, 3-49–3-54
phase suppression, 3-41, 3-50
procedure for displaying, 3-39
procedure for measuring, 3-42
record length, 3-45
empty, Saved waveform status, 3-133
Encapsulated Postscript, 3-59
Frame Length, Horizontal menu,
3-71
Enter Char, Labelling menu, 3-56,
3-57
Frame, Display menu, 3-31
Frame, Horizontal menu, 3-71
Frequency, 1-18, 3-87, Glossary-4
Front Cover removal, 1-4
Front panel, 2-4
Envelope acquisition mode, 3-5, 3-72,
Glossary-3
Envelope, Acquire menu, 3-7
EPS Color Img, Hardcopy menu,
3-61
Full, Display menu, 3-31
Full, Vertical menu, 3-149
Function, Cursor menu, 3-19, 3-20
Fuse, 1-3, 2-5
EPS Color Plt, Hardcopy menu, 3-61
EPS Mono Img, Hardcopy menu,
3-61
reducing noise, 3-47
undersampling, 3-48
zero phase reference, 3-49
EPS Mono Plt, Hardcopy menu, 3-61
Epson, 3-59
FFT time domain record, defined,
3-44
Epson, Hardcopy menu, 3-61
Equivalent time sampling, 2-21, 3-72
File System, 3-55–3-58
Optional File System, A-2
Equivalent-time sampling, random,
Glossary-3
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Hardcopy menu
BMP Color, 3-61
BMP Mono, 3-61
Clear Spool, 3-61, 3-62
Deskjet, 3-61
Holdoff, Main Trigger menu, 3-82,
G
3-121
Holdoff, trigger, 2-15, Glossary-5
Horiz Pos, Horizontal menu, 3-70
Horiz Scale, Horizontal menu, 3-70
Gated Measurements, 3-91, Glossa-
ry-4
DPU411–II, 3-61
DPU412, 3-61
Gating, Measure menu, 3-91
Horizontal, 3-10
General purpose (high input resis-
tance) probes, 3-112
EPS Color Img, 3-61
EPS Color Plt, 3-61
EPS Mono Img, 3-61
EPS Mono Plt, 3-61
Epson, 3-61
Format, 3-61
GPIB, 3-61
HPGL, 3-61
Interleaf, 3-61
Landscape, 3-61
Laserjet, 3-61
Layout, 3-61
OK Confirm Clear Spool, 3-62
PCX, 3-61
PCX Color, 3-61
Port, 3-61
Portrait, 3-61
RLE Color, 3-61
Thinkjet, 3-61
Bar cursors, 2-31, 3-17, Glossary-5
Control, 3-68–3-72
Menu, 2-18
Position, 3-68
POSITION knob, 2-26
Readouts, 3-69
Scale, 3-68
SCALE knob, 1-10, 2-26
System, 1-10, 2-26
General purpose knob, 1-19, 2-7,
Glossary-4
Glitch trigger, 3-119, 3-120, Glossa-
ry-4
Glitch, Main Trigger menu, 3-121,
3-122
Goes FALSE, Main Trigger menu,
3-81
Horizontal menu, 3-23
Delayed Only, 3-23
Delayed Runs After Main, 3-23,
Goes TRUE, Main Trigger menu, 3-81
GPIB, 2-5, 3-126–3-129, Glossary-4
GPIB, Hardcopy menu, 3-61
3-70
Delayed Scale, 3-70
Delayed Triggerable, 3-25, 3-70
FastFrame, 3-71
FastFrame Setup, 3-71
Fit to screen, 3-70
Frame, 3-71
Frame Count, 3-71
Frame Length%, 3-71
Frame%, 3-71
Horiz Pos, 3-70
Horiz Scale, 3-70
Intensified, 3-23, 3-25
Main Scale, 3-70
Record Length, 3-70
Set to 10%, 3-70
GPIB, Utility menu, 3-60, 3-128
Graticule, 3-31, Glossary-4
Measurements, 2-32
Graticule, Display menu, 3-31
Grid, Display menu, 3-31
TIFF, 3-61
Hardcopy, Color menu, 3-13
Hardcopy, Utility menu, 3-128
Hardware Setup, Utility menu, 3-60
HC100 Plotter, 3-59, A-2
HC220 Printer, 3-59
Ground coupling, Glossary-4
Ground lead inductance, 3-97
HELP button, 3-67
H
Set to 50%, 3-70
Help system, 3-67
Set to 90%, 3-70
Time Base, 3-23, 3-69
Trigger Position, 3-70
H Bars, Cursor menu, 3-19, 3-20
H Limit, Acquire menu, 3-74
Hamming window, 3-41
HF Rej, Main Trigger menu, 3-35
Hi Res acquisition mode, 3-5, Glossa-
ry-4
HORIZONTAL MENU button, 2-18,
Hi Res, Acquire menu, 3-7
3-23
Hanning window, 3-41
High, 3-87, Glossary-5
Horizontal POSITION knob, 3-68
Horizontal Readouts, 3-69
Horizontal SCALE knob, 3-68
HPGL, 3-59
Hard Flagging, Utility menu, 3-60
High frequency rejection, 2-16
High Ref, Measure menu, 3-93
High speed active probes, 3-114
High voltage probes, 3-113–3-114
Hardcopy, 3-59–3-66, Glossary-4
HC220, A-3
Phaser 200e, A-3
Hardcopy (Talk Only), Utility menu,
HPGL, Hardcopy menu, 3-61
Hue, Color menu, 3-14
3-60
High-Low Setup, Measure menu,
HARDCOPY button, 3-55, 3-61,
3-92
3-128
HiRes acquisition mode, 3-72
Hardcopy if Condition Met, Acquire
menu, 3-76
Histogram, Measure menu, 3-92
Hardcopy Interface, Optional
RS-232/Centronic, A-2
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Index
Trigger MAIN LEVEL, 1-11, 2-17
Vertical POSITION, 1-10, 2-26,
I
M
3-147
Vertical SCALE, 1-10, 2-26, 3-147
I/O, Status menu, 3-140
I/O, Utility menu, 3-60, 3-128
IC protector tip, 3-102
Icons, 1-1
Main menu, Glossary-6
Main menu buttons, 2-3, Glossary-6
Main Scale, Horizontal menu, 3-70
Main Trigger Menu
Falling edge, 3-36
Rising edge, 3-36
L
Independent Mode, Cursor,
2-31–2-32
Labelling menu, Enter Char, 3-56,
Main Trigger menu, 2-10, 3-34, 3-80,
3-121, 3-123, 3-145
Independent, Cursor menu, 3-20
3-57
Infinite Persistence, Display menu,
Landscape, Hardcopy menu, 3-61
Laserjet, 3-59
AC, 3-35
3-29
Accept Glitch, 3-122
AND, 3-82, 3-85
Auto, 3-37, 3-82, 3-121
Installation, 1-3–1-4
Laserjet, Hardcopy menu, 3-61
Layout, Hardcopy menu, 3-61
Level, Delayed Trigger menu, 3-26
Integral math waveform, 3-154
applications, 3-154
Ch1, Ch2 ..., 3-34, 3-81, 3-82,
3-84, 3-121, 3-123
Class, 3-80, 3-121, 3-123
Coupling, 3-35
automated measurements of,
3-157
derivation of, 3-154
magnifying, 3-153, 3-158
procedure for displaying, 3-154
procedure for measuring, 3-155
record length of, 3-154
Level, Main Trigger menu, 3-36,
3-122, 3-125
DC, 3-35
Define Inputs, 3-82, 3-84
Define Logic, 3-82, 3-85
Edge, 3-34, 3-145
Either, 3-122, 3-123
Falling edge, 3-84
Level, Trigger, 2-17
LF Rej, Main Trigger menu, 3-35
Lightness, Color menu, 3-14
Integration, Waveform, 3-154
Limit Test Condition Met, Acquire
Glitch, 3-121, 3-122
Goes FALSE, 3-81
Goes TRUE, 3-81
menu, 3-76
Intensified Samples, Display menu,
3-29
Limit Test Setup, Acquire menu,
3-75, 3-76
Intensified, Horizontal menu, 3-23,
HF Rej, 3-35
3-25
Limit Test Sources, Acquire menu,
Holdoff, 3-82, 3-121
Level, 3-36, 3-122, 3-125
LF Rej, 3-35
Mode & Holdoff, 3-37, 3-82, 3-121
NAND, 3-82, 3-85
Negative, 3-122, 3-123
Noise Rej, 3-35
NOR, 3-82, 3-85
3-75
Intensity, 3-29, Glossary-5
Intensity, Display menu, 3-29
Interleaf, 3-59
Limit Test, Acquire menu, 3-76
Limit testing, 3-73–3-77
Linear interpolation, 2-21, 3-31,
Glossary-5
Interleaf, Hardcopy menu, 3-61
Interleaving, 2-20, Glossary-5
Linear interpolation, Display menu,
Interpolation, 2-21, 3-31, Glossary-5
FFT distortion, 3-48
3-31
Normal, 3-37, 3-82, 3-121
OR, 3-82, 3-85
Pattern, 3-80
Logic trigger, 2-14, 3-80
Definitions, 3-80
linear versus sin(x)/x, 3-48
IRE (NTSC), Cursor menu, 3-21
Polarity, 3-123
Pattern, 3-79, Glossary-6
State, 3-79, Glossary-5
Polarity and Width, 3-122
Positive, 3-122, 3-123
Pulse, 3-121, 3-123, 3-145
Reject Glitch, 3-122
Rising edge, 3-84
Logic triggering, 3-78–3-85
Logic, Main Trigger menu, 3-145
Long ground leads, 3-100
K
Runt, 3-123
Low, 3-87, Glossary-6
Keypad, 1-20
Set Thresholds, 3-81
Set to 50%, 3-36, 3-123, 3-143
Set to ECL, 3-36, 3-122
Set to TTL, 3-36, 3-122
Slope, 3-36
Source, 3-34, 3-121, 3-123
State, 3-80, 3-84
Thresholds, 3-123
Low frequency rejection, 2-16
Low impedance Zo probes, 3-113
Low Ref, Measure menu, 3-93
Low-inductance ground lead, 3-100
Knob, Glossary-5
General purpose, 1-19, 2-7, Glos-
sary-4
Horizontal POSITION, 1-10, 2-26,
3-68
Horizontal SCALE, 1-10, 2-26,
3-68
MEASURE, 2-30
Low-inductance spring-tips, 3-101,
A-7
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Index
Trigger When, 3-81, 3-83
True for less than, 3-83
True for more than, 3-83
Type, 3-34, 3-121, 3-123, 3-145
Width, 3-122
Burst width, 3-86, Glossary-2
Cycle area, 3-86, Glossary-3
Cycle mean, 3-86, Glossary-3
Cycle RMS, 3-86, Glossary-3
Delay, 3-93, Glossary-3
Duty cycle, 1-18, Glossary-6,
Glossary-7
Fall time, 3-87
Measure, 2-10, 3-89, 3-96
More, 2-10, 3-39, 3-134, 3-150,
3-159
See also More menu
Operation, 2-7
Pop-up, 2-8, Glossary-7
Pulse trigger, 2-10
Save/Recall, 3-130
Save/Recall Setup, 2-10
Save/Recall Waveform, 2-10,
3-133
Setup, 1-7
Status, 2-10, 3-140–3-141
Utility, 2-11, 3-60, 3-128
MAIN TRIGGER OUTPUT, BNC, 2-5
Map Math, Color menu, 3-14
Map Reference, Color menu, 3-15
Marker rings, 3-100, A-7
Frequency, 1-18, 3-87, Glossary-4
Gated, Glossary-4
High, 3-87, Glossary-5
Low, 3-87, Glossary-6
Maximum, 3-87, Glossary-6
Mean, 3-87, Glossary-6
Minimum, 3-87, Glossary-6
Negative duty cycle, 3-87
Negative overshoot, 3-87
Negative width, 3-87
Overshoot, Glossary-8
Peak to peak, 3-87, Glossary-7
Period, 3-88, Glossary-7
Phase, 3-87, Glossary-7
Positive duty cycle, 3-88
Positive overshoot, 3-88
Positive width, 3-88
Math Waveform
Differential, A-3
FFT, A-3
Integral, A-3
Optional Advanced, A-3
Mid Ref, Measure menu, 3-93
Mid2 Ref, Measure menu, 3-93
Min-Max, Measure menu, 3-92
Minimum, 3-87, Glossary-6
Mode, Cursor, 2-31–2-32
Math waveform
derivative. See Derivative math
waveform
FFT. See FFT math waveform
integral. See Integral math wave-
form
Mode & Holdoff, Main Trigger menu,
3-37, 3-82, 3-121
Math waveforms, 3-159
Math, Color menu, 3-14
Math1/2/3, More menu, 3-159
Maximum, 3-87, Glossary-6
Mean, 3-87, Glossary-6
MEASURE button, 3-89
Mode, Acquire menu, 3-7
Model number location, 2-3
Monochrome, Color menu, 3-13
Propagation delay, 3-87
Readout, 3-89
Reference levels, 1-19
Rise time, 1-18, 3-88, Glossary-8
RMS, 3-88, Glossary-8
Undershoot, Glossary-6
MORE button, 3-75, 3-134, 3-136,
3-159
More menu, 2-10, 3-134, 3-150, 3-159
Average, 3-160
Measure Delay menu
Create Measrmnt, 3-95
Delay To, 3-93
Width, 1-18, Glossary-6, Glossa-
ry-8
Blackman-Harris, 3-41
Change Math waveform defini-
tion, 3-40, 3-150, 3-154, 3-160
dBV RMS, 3-40
diff, 3-151
Dual Wfm Math, 3-160
FFT, 3-40
Hamming, 3-41
Hanning, 3-41
intg, 3-155
Linear RMS, 3-40
Math1, Math2, Math3, 3-39, 3-150,
3-154
Math1/2/3, 3-159
No Process, 3-160
OK Create Math Waveform,
3-155, 3-160
Phase (deg), 3-40
Measurement Accuracy, Ensuring
maximum, 3-104–3-109,
3-138–3-139
Edges, 3-94
Measure Delay To, 3-93
OK Create Measurement, 3-95
Measurements, 2-30–2-32, 3-86–3-96
Algorithms, A-9–A-22
Automated, 1-17, 2-30
Cursor, 2-31, 3-17
Measure Delay To, Measure Delay
menu, 3-93
Measure menu, 2-10, 3-89, 3-96
Gating, 3-91
Gated, 3-91
Graticule, 2-32
Snapshot of, 3-95
High Ref, 3-93
High-Low Setup, 3-92
Histogram, 3-92
Low Ref, 3-93
Mid Ref, 3-93
Memory, Waveform, 3-134
Menu
Acquire, 3-7, 3-73
Color, 3-12
Cursor, 3-19
Delayed Trigger, 3-25–3-27
Display, 3-12, 3-28
File Utilities, 3-55
Horizontal, 2-18, 3-23
Main, 2-6
Mid2 Ref, 3-93
Min-Max, 3-92
Reference Levels, 3-92
Remove Measrmnt, 3-90, 3-96
Select Measrmnt, 3-89, 3-93
Set Levels in % units, 3-92
Snapshot, 3-96
Phase (rad), 3-40
Rectangular, 3-40
Reference waveform status, 3-134
Set 1st Source to, 3-161
Set 2nd Source to, 3-161
Set FFT Source to:, 3-40
Measurement
Main Trigger, 2-10, 3-34, 3-80,
3-121, 3-123, 3-145
Amplitude, 3-86, Glossary-1
Area, 3-86, Glossary-1
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Set FFT Vert Scale to:, 3-40
Set FFT Window to:, 3-40
Set Function to, 3-160
Set Function to:, 3-151, 3-155
Set operator to, 3-161
Set Single Source to, 3-160
OK Confirm Clear Spool, Hardcopy
Persistence Palette, Color menu,
menu, 3-62
3-13
OK Create Math Wfm, More menu,
Phase, 3-87, Glossary-7
Phase suppression, 3-50
3-160
OK Create Measurement, Measure
Phaser Color Printer, 3-59
200e, A-3
Delay menu, 3-95
Set Single Source to:, 3-150,
OK Erase Ref & Panel Memory,
3-154
Pixel, Glossary-7
Utility menu, 3-131
Single Wfm Math, 3-150, 3-154,
3-160
Plotter, HC100, 3-59, A-2
OK Store Template, Acquire menu,
3-74
Polarity and Width, Main Trigger
menu, 3-122
ON (Enable ET), Acquire menu, 3-7
ON/STBY button, 1-4, 2-3
Optical probes, 3-116
Polarity, Main Trigger menu, 3-123
Pop-up menu, 2-8, Glossary-7
Port, Hardcopy menu, 3-61
N
Option, Tutorial, A-2
NAND, Glossary-6
Port, Utility menu, 3-60, 3-128
Portrait, Hardcopy menu, 3-61
Options, A-1–A-8
NAND, Main Trigger menu, 3-82, 3-85
Negative duty cycle, 3-87
Negative overshoot, 3-87
Negative width, 3-87
Options, Color menu, 3-16
OR, Glossary-7
Position
Vertical, 2-26, 3-147
vertical, 3-46, 3-152, 3-157
OR, Main Trigger menu, 3-82, 3-85
Oscilloscope, Glossary-7
Overall, Display menu, 3-29
Overshoot, Glossary-8
Negative, Main Trigger menu, 3-122,
Position, Vertical menu, 3-149
Positive duty cycle, 3-88
Positive overshoot, 3-88
Positive width, 3-88
3-123
No Process, More menu, 3-160
Noise
Overwrite Lock, File Utilities menu,
reducing in FFTs, 3-47
reducing in phase FFTs, 3-41, 3-50
3-58
Positive, Main Trigger menu, 3-122,
3-123
Noise Rej, Main Trigger menu, 3-35
NOR, Glossary-7
Postscript, 3-59
Posttrigger, Glossary-8
Power connector, 1-4, 2-5
Power cords, A-1
P
NOR, Main Trigger menu, 3-82, 3-85
Normal trigger mode, 2-14, Glossa-
ry-7
Packaging, A-23
Paired cursor, 2-31, 3-17
PAL, Display menu, 3-31
Palette, Color menu, 3-13
Parity, Utility menu, 3-60
Passive voltage probes, 3-112–3-113
Pattern trigger, 3-78, 3-82
Pattern, Main Trigger menu, 3-80
PCX, 3-59
Normal, Color menu, 3-13
Power off, 1-5
Normal, Main Trigger menu, 3-37,
Power on, 1-4–1-5
3-82, 3-121
Pretrigger, Glossary-8
Principal power switch, 1-4, 2-5
Print, File Utilities menu, 3-57
NTSC, Display menu, 3-31
Nyquist frequency, 3-48
Printer
HC220, 3-59, A-3
Phaser, 3-59
Phaser 200e, A-3
O
PCX Color, Hardcopy menu, 3-61
PCX, Hardcopy menu, 3-61
Probe accessories
OFF (Real Time Only), Acquire
Bayonet ground assembly, A-7
Compact-to-miniature probe tip
adapter, 3-102, A-7
menu, 3-7
Peak detect acquisition mode, 3-3,
Glossary-7
Off Bus, Utility menu, 3-128
Dual-lead adapter, 3-103
IC protector tip, 3-102
Long ground leads, 3-100
Low-inductance ground lead, 3-100
Offset
Peak Detect, Acquire menu, 3-7
Peak to peak, 3-87, Glossary-7
Period, 3-88, Glossary-7
Persistence, 3-29
DC. See DC Offset
Vertical, 2-26, 3-149
vertical, 3-46, 3-152, 3-157
Offset, Vertical menu, 3-149
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Index
Low-inductance spring-tips, 3-101,
A-7
Marker rings, 3-100, A-7
Probe tip-to-chassis adapter,
3-102, A-7
Probe tip-to-circuit board adapters,
3-101
Reference Levels, Measure menu,
R
3-92
Reference memory, Glossary-8
Rack mounting, A-2
Reject Glitch, Main Trigger menu,
Readout
3-122
Acquisition, 3-6
Channel, 2-6, 3-136
Cursors, 2-6
Edge trigger, 3-34, 3-79
General purpose knob, 2-6
Measurement, 2-31, 3-89
Record view, 2-6
Snapshot, 3-95
Remote communication, 3-126–3-129
Retractable hook tip, 3-98
SMT KlipChip, 3-101, A-7
Remove Measrmnt, Measure menu,
3-90, 3-96
Probe Cal, 3-104–3-109
Rename, File Utilities menu, 3-56
Probe tip-to-chassis adapter, 3-102,
A-7
Repetitive Signal, Acquire menu, 3-7
Reset All Mappings To Factory,
Probe tip-to-circuit board adapters,
3-101
Color menu, 3-16
Time base, 2-6
Trigger, 2-6, 3-144
Trigger Level Bar, 3-30
Trigger Point, 3-30
Reset All Palettes To Factory, Color
Probes
menu, 3-16
Accessories, 3-98–3-103, A-4,
A-5–A-8
Reset Current Palette To Factory,
Readout, Cursor, Paired, 3-152
Color menu, 3-16
Active, A-3
Active voltage, 3-114–3-115
Additional, A-3
By applications, 3-117, 3-118
Compensation, 1-10, 3-110, Glos-
sary-8
Readout, cursor
Reset to Factory Color, Color menu,
3-14
H-Bars, 3-42, 3-152, 3-156
Paired cursors, 3-43, 3-156
V-Bars, 3-42, 3-152, 3-156
Reset Zoom Factors, Zoom menu,
3-164
Readout, Display menu, 3-30
Real time sampling, 2-20
Restore Colors, Color menu, 3-16
Connection, 1-6, 3-97–3-103
Current, 3-115
Definition, Glossary-8
Differential active, 3-114
Fixtured active, 3-114
Retractable hook tip, 3-98
Real-time sampling, Glossary-8
Rear panel, 2-5, 3-128
Ring Bell if Condition Met, Acquire
menu, 3-76
Rise time, 1-18, 3-88, Glossary-8
General purpose (high input resis-
tance), 3-112
High speed, 3-114
High voltage, 3-113–3-114
Low impedance Zo, 3-113
Optical, 3-116
Recall, Setups, 3-130–3-132
Rising edge, Delayed Trigger menu,
3-26
Recall Factory Setup, Save/Recall
Setup menu, 3-131
Rising edge, Main Trigger menu,
3-36, 3-84
Recall Saved Setup, Save/Recall
Setup menu, 3-131
RLE Color, Hardcopy menu, 3-61
RMS, 3-88, Glossary-8
RS-232, 2-5
Passive, 3-110
Recalling, Waveforms, 3-133
Passive voltage, 3-112–3-113
Selection, 3-112–3-118
SMD, A-3
Record length, 1-1, 2-20, 3-70, A-1,
Glossary-8
derivative math waveforms, 3-150
integral math waveforms, 3-154
Time-to-voltage converter, 3-116
RS-232, Port, 3-61
Propagation delay, 3-87
Pulse trigger, 2-14, 3-119
Pulse Trigger menu, 2-10
RS232, Utility menu, 3-60
RUN/STOP, 3-72
Record Length, Horizontal menu,
3-70
Record View, 2-6, 2-25, 3-69, 3-144
Rectangular window, 3-40
Ref, Color menu, 3-15
RUN/STOP, Acquire menu, 3-8
Pulse, Main Trigger menu, 3-121,
Runt trigger, 3-119, 3-120, 3-123,
Glossary-9
3-123, 3-145
Runt, Main Trigger menu, 3-123
Ref1, Ref2, Ref3, Ref4, File, Save/
Recall Waveform menu, 3-134
Ref1, Ref2, Ref3, Ref4, Reference
Q
waveform status, 3-134
Reference levels, 1-19, 3-92
Quantizing, Glossary-8
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Index
Serial number, 2-5
Single-Shot sampling, 2-20
Slope, Glossary-9
S
Set 1st Source to, More menu, 3-161
Set 2nd Source to, More menu,
Slope, Delayed Trigger menu, 3-26
Slope, Main Trigger menu, 3-36
Slope, Trigger, 2-17
Safety, v
3-161
Symbols, v
Set Function to, More menu, 3-160
Sample acquisition mode, 3-3, Glos-
sary-9
SET LEVEL TO 50% button, 3-143
SMT KlipChip, 3-101, A-7
Snapshot, Readout, 3-95
Sample interval, Glossary-9
Sample, Acquire menu, 3-7
Sampling, 2-20, Glossary-9
Sampling and acquisition mode, 2-22
Saturation, Color menu, 3-14
Save, Setups, 3-130–3-132
Set Levels in % units, Measure
menu, 3-92
Snapshot of Measurements, 1-21,
3-95
Set operator to, More menu, 3-161
Set Single Source to, More menu,
Snapshot, Measure menu, 3-96
Soft Flagging, Utility menu, 3-60
Software, 1-1
3-160
Set Thresholds, Main Trigger menu,
3-81
Save Current Setup, Save/Recall
Set to 10%, Horizontal menu, 3-70
Software Setup, Utility menu, 3-60
Software version, 3-140
Setup menu, 3-130
Set to 50%, Delayed Trigger menu,
Save Waveform, Save/Recall Wave-
3-27
Source, Delayed Trigger menu, 3-26
form menu, 3-133
Set to 50%, Horizontal menu, 3-70
Source, Main Trigger menu, 3-34,
Save/Recall SETUP button, 1-7, 3-55,
Set to 50%, Main Trigger menu, 3-36,
3-121, 3-123
3-130
3-123, 3-143
Spectral, Color menu, 3-13
Spooler, Hardcopy, 3-62
Start up, 1-3
Save/Recall Setup menu, 2-10, 3-130
factory status, 3-130
Set to 90%, Horizontal menu, 3-70
File Utilities, 3-132
Set to ECL, Delayed Trigger menu,
3-26
Recall Factory Setup, 3-131
Recall Saved Setup, 3-131
Save Current Setup, 3-130
user status, 3-130
State trigger, 3-84
Set to ECL, Main Trigger menu, 3-36,
3-122
State, Main Trigger menu, 3-80, 3-84
STATUS button, 3-140
Set to TTL, Delayed Trigger menu,
Save/Recall WAVEFORM button,
3-26
Status menu, 2-10, 3-140–3-141
Display, 3-140
3-55, 3-133
Set to TTL, Main Trigger menu, 3-36,
Save/Recall Waveform menu, 2-10,
3-133
3-122
Firmware version, 3-140
I/O, 3-140
System, 3-140
Trigger, 3-140
Waveforms, 3-140
Set to Zero, Vertical menu, 3-149
Setting Up for the Examples, 1-6
Settings, Display menu, 3-12, 3-28
Setup menu, 1-7
active status, 3-133
Delete Refs, 3-134
empty status, 3-133
File Utilities, 3-135
Ref1, Ref2, Ref3, Ref4, File, 3-134
Save Waveform, 3-133
Stop After Limit Test Condition Met,
Acquire menu, 3-76
Setups, Save and recall, 3-130–3-132
Shipping, A-23
Stop After, Acquire menu, 3-8, 3-76
Stop Bits, Utility menu, 3-60
Style, Display menu, 3-28
Saving, Waveforms, 3-133
Saving and recalling setups, 1-23,
3-130
Side menu, Glossary-9
Side menu buttons, 2-3, Glossary-9
SIGNAL OUTPUT, BNC, 2-5
Saving and recalling waveforms,
3-133
Switch, principal power, 1-4, 2-5
System, Status menu, 3-140
System, Utility menu, 3-60, 3-128
Signal Path Compensation, 1-3,
3-138–3-139
Scale, vertical, 3-46, 3-152, 3-157
seconds, Cursor menu, 3-21
Sin(x)/x interpolation, 2-21, 3-31,
Glossary-5
SELECT button, 2-31, 3-20, Glossa-
ry-9
Sin(x)/x interpolation, Display menu,
Select Measrmnt, Measure menu,
3-31
T
3-89, 3-93
Single Acquisition Sequence,
Selected waveform, Glossary-9
Selecting channels, 3-136
Self test, 1-5
Acquire menu, 3-8
Talk/Listen Address, Utility menu,
SINGLE TRIG button, 3-8, 3-143
3-128
Single Wfm Math, More menu, 3-160
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Tek Secure, 3-131, Glossary-9
Trigger Bar Style, Display menu,
Stop Bits, 3-60
System, 3-60, 3-128
Talk/Listen Address, 3-128
3-30
Tek Secure Erase Memory, Utility
menu, 3-131
Trigger Level Bar, Readout, 3-30,
3-72
Temperature compensation,
3-138–3-139
Trigger MAIN LEVEL knob, 1-11,
2-17, 3-142
Temperature, Color menu, 3-13
V
TRIGGER MENU button, 3-34, 3-80,
Template Source, Acquire menu,
3-121, 3-123, 3-145
3-73
V Limit, Acquire menu, 3-74
Trigger Point, Readout, 3-30, 3-72
Text/Grat, Display menu, 3-29
Thinkjet, 3-59
Variable Persistence, Display menu,
Trigger Position, Horizontal menu,
3-29
3-70
Thinkjet, Hardcopy menu, 3-61
Vectors, 3-29
Trigger Status Lights, 3-143
Thresholds, Main Trigger menu,
Vectors, Display menu, 3-29
Trigger When, Main Trigger menu,
3-123
3-81, 3-83
Vertical, 3-10
TIFF, 3-59
Trigger, Status menu, 3-140
Bar cursors, 2-31, 3-17, Glossa-
ry-10
TIFF, Hardcopy menu, 3-61
Time base, Glossary-10
True for less than, Main Trigger
Control, 3-147–3-149
Offset, 2-26, 3-149
Position, 2-26, 3-147
POSITION knob, 2-26
Readout, 3-147
Scale, 3-147
SCALE knob, 1-10, 2-26
System, 1-10, 2-26
menu, 3-83
True for more than, Main Trigger
Time Base, Horizontal menu, 3-23,
menu, 3-83
3-69
Tutorial, Option, A-2
Time Units, Cursor menu, 3-21
Time-to-voltage converter, 3-116
TOGGLE button, 3-20
Type, Main Trigger menu, 3-34,
3-121, 3-123, 3-145
Tracking Mode, Cursor, 2-32
Tracking, Cursor menu, 3-20
Vertical Menu, Cal Probe, 3-104
Vertical menu
100 MHz, 3-149
20 MHz, 3-149
Bandwidth, 3-149
Coupling, 3-148
Fine Scale, 3-149
Full, 3-149
Offset, 3-149
Position, 3-149
Set to Zero, 3-149
U
Trigger, 2-13–2-18, 3-10, Glossary-10
AC Line Voltage, 2-14
Auxiliary, 2-14
Undershoot, Glossary-6
user, Saved setup status, 3-130
UTILITY button, 3-60, 3-128
Utility Menu
Coupling, 2-16
Delay, 2-18
Delayed, 3-22–3-27
Edge, 2-14, 3-34, Glossary-3
Glitch, 3-119, 3-120, Glossary-4
Holdoff, 2-15
OK Erase Ref & Panel Memory,
3-131
Level, 2-17, Glossary-10
Logic, 2-14, 3-78–3-85
Mode, 2-14
Pattern, 3-78, 3-82
Position, 2-17, 3-70, 3-72
Pulse, 2-14, 3-119
Readout, 3-144
Runt, 3-119, 3-120, 3-123, Glossa-
ry-9
Slope, 2-13, 2-17
Source, 2-13
State, 3-84
Status Lights, 3-143
Types, 3-145–3-146
Video, 2-14
VERTICAL MENU button, 1-14
Tek Secure Erase Memory, 3-131
Vertical position, for DC correction of
FFTs, 3-46
Utility menu, 2-11, 3-60, 3-128
Baud Rate, 3-60
Configure, 3-60, 3-128
GPIB, 3-60, 3-128
Hard Flagging, 3-60
Hardcopy, 3-128
Hardcopy (Talk Only), 3-60
Hardware Setup, 3-60
I/O, 3-60, 3-128
Off Bus, 3-128
Parity, 3-60
Port, 3-60, 3-128
RS232, 3-60
Vertical POSITION knob, 3-147
Vertical Readout, 3-147
Vertical SCALE knob, 3-147
VGA Output, 2-5
Video Line Number, Cursor menu,
3-21
Video Trigger, Option 5, A-3
Video trigger, 2-14
View Palette, Color menu, 3-13
Soft Flagging, 3-60
Software Setup, 3-60
Width, 3-119, 3-125
Trigger Bar, 2-6, 3-72
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Index
Waveforms, Status menu, 3-140
Width, 1-18, Glossary-6, Glossary-8
Width trigger, 3-119, 3-125
W
Y
WARNING, statement in manual, v
YT, Format, 3-31–3-33
YT format, Glossary-10
YT, Display menu, 3-32
Width, Main Trigger menu, 3-122
Waveform, Glossary-10
Interval, Glossary-10
Math, 3-159–3-161
Off priority, 3-137
Window, 3-51
Blackman-Harris, 3-41, 3-51, 3-54
characteristics of, 3-53
Hamming, 3-41, 3-51, 3-54
Hanning, 3-41, 3-51, 3-54
rectangular, 3-40, 3-51, 3-54
rectangular vs. bell-shaped, 3-53
selecting, 3-51
Waveform clipping. See Clipping
Waveform differentiation, 3-150
Waveform FFTs, 3-38
Z
Zero phase reference point, 3-44,
3-49
Waveform integration, 3-154
Waveform memory, 3-134
Windowing, process, 3-51
establishing for impulse testing,
3-49–3-54
Windows, descriptions of, 3-40–3-41
WAVEFORM OFF button, 1-16, 3-32,
3-137
Zoom, 3-162–3-164
derivative math waveforms, 3-153
on FFT math waveforms, 3-47
on integral math waveforms, 3-158
Waveform record
FFT, 3-44
FFT frequency domain, 3-44
length of, 3-44
FFT source, 3-44
acquisition mode, 3-47
defined, 3-44
X
ZOOM button, 3-162
XY, Format, 3-31–3-33
XY format, Glossary-10
XY, Display menu, 3-32
Zoom feature, 2-28
Zoom menu
long versus short, 3-47
Reset Zoom Factors, 3-164
Zoom Off, 3-164
FFT time domain, 3-44–3-54
Waveform, Display menu, 3-29
Waveforms, Math, 3-159
Zoom Off, Zoom menu, 3-164
Index
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