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User Manual
TDS 200-Series Digital Real-Time Oscilloscope 071-0398-03
This document supports firmware version FV:v1.00 and above.
www.tektronix.com
Copyright © Tektronix, Inc. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes that in all previously published material. Specifications and price change privileges reserved. Tektronix, Inc., P.O. Box 500, Beaverton, OR 97077 TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.
WARRANTY SUMMARY (TDS 200-Series Digitizing Oscilloscope)
Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of three (3) years from the date of shipment from an authorized Tektronix distributor. If a product or CRT proves defective within the respective period, Tektronix will provide repair or replacement as described in the complete warranty statement. To arrange for service or obtain a copy of the complete warranty statement, please contact your nearest Tektronix sales and service office. EXCEPT AS PROVIDED IN THIS SUMMARY OR THE APPLICABLE WARRANTY STATEMENT, TEKTRONIX MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL TEKTRONIX BE LIABLE FOR INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES.
WARRANTY SUMMARY (P2100 Probe)
Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment. If a product proves defective within the respective period, Tektronix will provide repair or replacement as described in the complete warranty statement. To arrange for service or obtain a copy of the complete warranty statement, please contact your nearest Tektronix sales and service office. EXCEPT AS PROVIDED IN THIS SUMMARY OR THE APPLICABLE WARRANTY STATEMENT, TEKTRONIX MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL TEKTRONIX BE LIABLE FOR INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES.
Table of Contents
General Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . Contacting Tektronix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Product End-of-Life Handling . . . . . . . . . . . . . . . . . . . . . . . . Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Cord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Security Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Extension Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Probe Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Self Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Probe Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Probe Attenuation Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Basic Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Holdoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Slope and Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acquiring Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acquisition Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Time Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scaling and Positioning Waveforms . . . . . . . . . . . . . . . . . . . . . Vertical Scale and Position . . . . . . . . . . . . . . . . . . . . . . . . . . Horizontal Scale and Position; Pretrigger Information . . . . Taking Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Graticule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setting Up the Oscilloscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using Autoset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Saving a Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recalling a Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defaults (Factory Setup) . . . . . . . . . . . . . . . . . . . . . . . . . . . v vii viii 1 2 3 3 3 4 5 6 7 7 8 9 10 10 11 11 13 14 14 14 15 15 16 16 17 17 20 20 21 21 21 22 22 22 22
TDS 200-Series Digital Oscilloscope User Manual
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Table of Contents
Operating Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Display Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Menu System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Circular List Menu Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . Action Button Menu Boxes . . . . . . . . . . . . . . . . . . . . . . . . . Radio Button Menu Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . Page Selection Menu Boxes . . . . . . . . . . . . . . . . . . . . . . . . . Waveform Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vertical Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Horizontal Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trigger Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Menu and Control Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Taking Simple Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . Using Autoset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Taking Automatic Measurements . . . . . . . . . . . . . . . . . . . . Measuring Two Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . Taking Cursor Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . Measuring Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measuring Rise Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measuring Ring Frequency . . . . . . . . . . . . . . . . . . . . . . . . . Measuring Ring Amplitude . . . . . . . . . . . . . . . . . . . . . . . . . Analyzing Signal Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Looking at a Noisy Signal . . . . . . . . . . . . . . . . . . . . . . . . . . Separating the Signal from Noise . . . . . . . . . . . . . . . . . . . . Capturing a Single-Shot Signal . . . . . . . . . . . . . . . . . . . . . . . . . Optimizing the Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . Measuring Propagation Delay . . . . . . . . . . . . . . . . . . . . . . . . . . Triggering on a Video Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . Triggering on Video Fields . . . . . . . . . . . . . . . . . . . . . . . . . Triggering on Video Lines . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Window Function to See Waveform Details . . . . Triggering on Odd or Even Video Fields . . . . . . . . . . . . . . . Analyzing a Differential Communication Signal . . . . . . . . . . . TDS 210 and TDS 220 (Firmware V 2.00 and Above), and TDS 224 (All Versions) Oscilloscopes . . . . . . . . . . . . . . . . TDS 210 and TDS 220 Oscilloscopes (Firmware Below V 2.00) without a TDS2MM . . . . . . . . . . . . . . . . . . . . . . . . TDS 210 and TDS 220 Oscilloscopes (Firmware Below V 2.00) with a TDS2MM . . . . . . . . . . . . . . . . . . . . . . . . . . . Viewing Impedance Changes in a Network . . . . . . . . . . . . . . . .
23 24 26 26 27 27 27 28 29 31 32 33 35 37 38 38 39 40 42 42 43 45 46 47 47 48 49 50 51 53 54 54 55 57 60 61 62 62 63
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TDS 200-Series Digital Oscilloscope User Manual
Table of Contents
Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acquire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Autoset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Horizontal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Math . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TDS 210 and TDS 220 (Firmware V 2.00 and Above) and TDS 224 (All Versions) Oscilloscopes . . . . . . . . . . . . . . . . , TDS 210 and TDS 220 Oscilloscopes (Firmware Below V 2.00) without a TDS2MM . . . . . . . . . . . . . . . . . . . . . . . . TDS 210 and TDS 220 Oscilloscopes (Firmware Below V 2.00) with a TDS2MM . . . . . . . . . . . . . . . . . . . . . . . . . . Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Save/Recall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trigger Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vertical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hard Copy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix A: Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix B: Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix C: General Care and Cleaning . . . . . . . . . . . . . . . Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65 66 70 71 72 74 76 76 77 77 79 81 83 87 89 90 91 103 107 109 115
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Table of Contents
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TDS 200-Series Digital Oscilloscope User Manual
General Safety Summary
Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. To avoid potential hazards, use this product only as specified. Only qualified personnel should perform service procedures.
To Avoid Fire or Personal Injury
Use Proper Power Cord. Use only the power cord specified for this product and certified for the country of use. Connect and Disconnect Properly. Do not connect or disconnect probes or test leads while they are connected to a voltage source. Ground the Product. This product is grounded through the grounding
conductor of the power cord. To avoid electric shock, the grounding conductor must be connected to earth ground. Before making connections to the input or output terminals of the product, ensure that the product is properly grounded.
Connect the Probe Properly. The probe ground lead is at ground potential. Do not connect the ground lead to an elevated voltage. Observe All Terminal Ratings. To avoid fire or shock hazard, observe all
ratings and marking on the product. Consult the product manual for further ratings information before making connections to the product.
Do Not Operate Without Covers. Do not operate this product with
covers or panels removed.
Use Proper Fuse. Use only the fuse type and rating specified for this
product.
Avoid Exposed Circuitry. Do not touch exposed connections and
components when power is present.
Do Not Operate With Suspected Failures. If you suspect there is damage
to this product, have it inspected by qualified service personnel.
Provide Proper Ventilation. Refer to the manual's installation
instructions for details on installing the product so it has proper ventilation.
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General Safety Summary
Do Not Operate in Wet/Damp Conditions. Do Not Operate in an Explosive Atmosphere. Keep Product Surfaces Clean and Dry.
Safety Terms and Symbols
Terms in This Manual. These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that could result in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that could result in damage to this product or other property.
Terms on the Product. These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the marking. WARNING indicates an injury hazard not immediately accessible as you read the marking. CAUTION indicates a hazard to property including the product.
Symbols on the Product. These symbols may appear on the product:
Protective Ground (Earth) Terminal
Measurment Ground Terminal
CAUTION Refer to Manual
Measurment Input Terminal
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TDS 200-Series Digital Oscilloscope User Manual
Contacting Tektronix
Product support For questions about using Tektronix measurement products, call toll free in North America: 1-800-8339200 6:00 a.m. 5:00 p.m. Pacific time Or contact us by e-mail: [email protected] For product support outside of North America, contact your local Tektronix distributor or sales office. Service support Tektronix offers extended warranty and calibration programs as options on many products. Contact your local Tektronix distributor or sales office. For a listing of worldwide service centers, visit our web site. For other In North America: information 1-8008339200 An operator can direct your call. To write us Tektronix, Inc. P.O. Box 500 Beaverton, OR 97077-0001 USA www.tektronix.com
Web site
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Contacting Tektronix
Product End-of-Life Handling
Components that Contain Mercury. The cold cathode fluorescent tube
located in the liquid crystal display backlight contains trace elements of mercury. When you are ready to reclaim the instrument, you must properly transfer it according to local regulations concerning mercury-containing equipment or ship the instrument to the Tektronix Recycling Operations (RAMS). You can contact Tektronix for the RAMS shipping address and instructions.
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TDS 200-Series Digital Oscilloscope User Manual
Getting Started
TDS 200-Series Digital Oscilloscopes are small, lightweight, benchtop packages that you can use to take ground-referenced measurements. The TDS 210 and TDS 220 oscilloscopes have two-channels; the TDS 224 has four channels. In addition to the list of general features, this section covers the following topics: H How to install your product H How to add extended functions H How to perform a brief functional check H How to compensate probes H How to use the self calibration routine H How to match your probe attenuation factor NOTE. To select a display language, push the UTILITY menu button, and then push the Language menu box item to select the appropriate language.
TDS 200-Series Digital Oscilloscope User Manual
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Getting Started
General Features
H 100 MHz (TDS 220 or TDS 224) or 60 MHz (TDS 210) bandwidth with selectable 20 MHz bandwidth limit H 1 GS/s sample rate and 2,500 point record length for each channel H Cursors with readout H Five automated measurements H High-resolution, high-contrast LCD display with temperature compensation and replaceable back light H Setup and waveform storage H Autoset for quick setup H Waveform averaging and peak detection H Digital real-time oscilloscope H Dual time base H Video trigger capability H RS-232, GPIB, and Centronics communication ports easily added with optional extension modules H Variable persistence display H User interface available in ten user-selectable languages
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TDS 200-Series Digital Oscilloscope User Manual
Getting Started
Installation
Power Cord Use only power cords designed for your oscilloscope. Use a power source that delivers 90 to 264 VACRMS, 45 to 440 Hz. Refer to page 105 for a list of available power cords. Use the power cord notch to help route the cord to the rear of the instrument and avoid inadvertently disconnecting the power source.
Power cord notch
Securing cable
Security Loop Use the built-in cable channels to secure both your instrument and extension module to your location.
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Getting Started
Extension Modules
You can increase the feature set of your oscilloscope by inserting an extension module. Refer to page 103 for information about the available modules. CAUTION. Electrostatic discharge (ESD) can damage components in the extension module and the oscilloscope. Do not operate your instrument with the extension module connector exposed.
Modules slide in and out
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TDS 200-Series Digital Oscilloscope User Manual
Getting Started
Functional Check
Perform this quick functional check to verify that your instrument is operating correctly.
ON/OFF button
1. Turn on the instrument. Wait until the display shows that all self tests passed. Push the SAVE/RECALL button, select Setups in the top menu box and push the Recall Factory menu box. The default Probe menu attenuation setting is 10X.
PROBE COMP
PASSED
2. Set the switch to 10X on the P2100 probe and connect the probe to channel 1 on the oscilloscope. To do this, align the slot in the probe connector with the key on the CH 1 BNC, push to connect, and twist to the right to lock the probe in place.
CH 1
Attach the probe tip and reference lead to the PROBE COMP connectors. 3. Push the AUTOSET button. Within a few seconds, you should see a square wave in the display (approximately 5 V at 1 kHz peak-to-peak). Push the CH 1 MENU button twice to turn off channel 1, push the CH 2 MENU button to turn on channel 2, repeat steps 2 and 3. For TDS 224, repeat for CH 3 and CH 4.
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Getting Started
Probe Compensation
Perform this adjustment to match your probe to the input channel. This should be done whenever you attach a probe for the first time to any input channel.
PROBE COMP AUTOSET button
1. Set the Probe menu attenuation to 10X. Set the switch to 10X on the P2100 probe and connect the probe to channel 1 on the oscilloscope. If you use the probe hooktip, ensure a proper connection by firmly inserting the tip onto the probe. Attach the probe tip to the PROBE COMP 5V connector and the reference lead to the PROBE COMP Ground connector, turn on the channel, and then press AUTOSET. 2. Check the shape of the displayed waveform.
CH 1
Overcompensated
Undercompensated
Compensated correctly
3. If necessary, adjust your probe. Repeat as necessary.
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TDS 200-Series Digital Oscilloscope User Manual
Getting Started
Self Calibration
The self calibration routine lets you quickly optimize the oscilloscope signal path for maximum measurement accuracy. You can run the routine at anytime but you should always run the routine if the ambient temperature changes by 5_ C or more. To compensate the signal path, disconnect any probes or cables from the input connectors. Then, press the UTILITY button and select Do Self Cal to confirm that you are ready to proceed.
Probe Safety
A guard around the probe body provides a finger barrier for protection from electric shock.
Finger guard
WARNING. To avoid electric shock when using the probe, keep fingers behind the guard on the probe body. To avoid electric shock while using the probe, do not touch metallic portions of the probe head while it is connected to a voltage source. Connect the probe to the instrument and connect the ground terminal to ground before you take any measurements.
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Getting Started
Probe Attenuation Setting
Probes are available with various attenuation factors which affect the vertical scale of the signal. To change (or check) the probe attenuation setting, press the VERTICAL MENU button (of the channel you are using), and then press the menu selection next to Probe until the correct setting is displayed. This setting remains in effect until changed again. NOTE. The default Probe menu attenuation setting is 10X when the oscilloscope is shipped. Be sure that the Attenuation switch on the P2100 probe is set to match the Probe menu selection in the oscilloscope. The probe switch settings are 1X and 10X.
Attenuation switch
NOTE. When the Attenuation switch is set to 1X, the P2100 probe limits the bandwidth of the oscilloscope to 7 MHz. To use the full bandwidth of the oscilloscope, be sure to set the switch to 10X.
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TDS 200-Series Digital Oscilloscope User Manual
Basic Concepts
To use your oscilloscope effectively, you must understand the following basic concepts: H Triggering H Acquiring data H Scaling and positioning waveforms H Measuring waveforms H Setting Up the oscilloscope The figure below shows a block diagram of the various functions of an oscilloscope and their relationship to each other.
Each channel
Vertical: gain and position
Acquire data: mode and time base
Waveform record: 2500 points
Display Computer interface (TDS2CM)
Ext AC Line
Trigger
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Basic Concepts
Triggering
The trigger determines when the oscilloscope starts to acquire data and display a waveform. When a trigger is set up properly, it can convert unstable displays or blank screens into meaningful waveforms.
Triggered waveform
Untriggered waveforms
When the oscilloscope starts to acquire a waveform, it collects enough data so that it can draw the waveform to the left of the trigger point. The oscilloscope continues to acquire data while waiting for the trigger condition to occur. After it detects a trigger, the oscilloscope continues to acquire enough data so that it can draw the waveform to the right of the trigger point. Source You can derive your trigger from various sources: Input channels, AC Line, and External.
Input. The most commonly used trigger source is any one of the input
channels. The channel you select as a trigger source will function whether it is displayed or not.
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TDS 200-Series Digital Oscilloscope User Manual
Basic Concepts
AC Line. You can use this trigger source when you want to look at
signals related to the power line frequency, such as lighting equipment and power supply devices. The oscilloscope generates the trigger, so you do not have to input a trigger signal.
External (TDS 210 and TDS 220 Only). You can use this trigger source
when you want to acquire data on two channels and trigger from a third. For example, you might want to trigger from an external clock or with a signal from another part of the test circuit. The EXT and EXT/5 trigger sources both use the external trigger signal connected to the EXT TRIG connector. EXT uses the signal directly; you can use EXT on signals with a trigger level range of +1.6 V to 1.6 V. The EXT/5 trigger source divides the signal by 5 which extends the trigger level range from + 8 V to 8 V. This allows the oscilloscope to trigger on a larger signal. Types The oscilloscope provides two types of triggers: Edge and Video.
Edge. You can use the edge trigger with analog and digital test
circuits. An edge trigger occurs when the trigger input passes through a specified voltage level in the specified direction.
Video. You can use the video trigger on fields or lines of standard
video signals. Refer to Triggering on a Video Signal on page 53. Modes The trigger mode determines how the oscilloscope behaves in the absence of a trigger event. The oscilloscope provides three trigger modes: Auto, Normal, and Single.
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Basic Concepts
Auto. This trigger mode allows the oscilloscope to acquire a waveform even when it does not detect a trigger condition. If no trigger condition occurs while the oscilloscope waits for a specific period (as determined by the time-base setting), it will force itself to trigger.
Refer to Time Base on page 16 for more information on time bases. When forcing invalid triggers, the oscilloscope cannot synchronize the waveform, and the waveform seems to roll across the display. If valid triggers occur, the display becomes stable on the screen. You can use Auto mode to monitor an amplitude level, such as a power supply output, which may cause the waveform to roll across the display.
Normal. The Normal mode allows the oscilloscope to acquire a
waveform only when it is triggered. If no trigger occurs, the oscilloscope will not acquire a new waveform, and the previous waveform, if any, will remain on the display.
Single. The Single mode allows the oscilloscope to acquire one
waveform each time you press the RUN button, and the trigger condition is detected. The data that the oscilloscope acquires depends on the acquisition mode. Refer to Acquisition Modes on page 15 for more information on the type of data each acquisition mode will acquire. NOTE. When you use the Single trigger mode with the Average acquisition mode, the number of waveforms specified in the number of averages are acquired before the acquisition stops.
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TDS 200-Series Digital Oscilloscope User Manual
Basic Concepts
Holdoff Triggers are not recognized during holdoff time (the period that follows each acquisition). For some signals, you need to adjust the holdoff period to produce a stable display. The trigger signal can be a complex waveform with many possible trigger points on it, such as a digital pulse train. Even though the waveform is repetitive, a simple trigger might result in a series of patterns on the screen instead of the same pattern each time.
Acquisition interval Acquisition interval Holdoff Acquisition interval
Trigger level Indicates trigger points
Holdoff Holdoff Triggers are not recognized during holdoff time.
Holdoff
For example, you could use the holdoff period to prevent triggering on any other pulse except the first one in a pulse train. This way, the oscilloscope would always display the first pulse. To access the Holdoff control, press the HORIZONTAL Menu button, select Holdoff, and use the HOLDOFF knob to change the amount of time in the holdoff period.
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Basic Concepts
Coupling Trigger coupling determines what part of the signal passes on to the trigger circuit. Coupling types include DC, AC, Noise Rejection, High Frequency Rejection, and Low Frequency Rejection.
DC. DC coupling passes both AC and DC components. AC. AC coupling blocks DC components. Noise Rejection. Noise Reject coupling lowers the trigger sensitivity
and requires more signal amplitude for stable triggering. This reduces the chance of falsely triggering on noise.
High Frequency Rejection. HF Reject coupling blocks the high
frequency portion and passes on only the low frequency components.
Low Frequency Rejection. LF Reject coupling does the opposite of high
frequency rejection. Position The horizontal position control establishes the time between the trigger and the screen center. Refer to Horizontal Scale and Position; Pretrigger Information on page 17 for more information on how to use this control to position the trigger. Slope and Level The Slope and Level controls help to define the trigger. The Slope control determines whether the oscilloscope finds the trigger point on the rising or the falling edge of a signal. To access the trigger slope control, press the TRIGGER Menu button, select Edge, and use the Slope button to select Rising or Falling.
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The Level control determines where on the edge the trigger point occurs. To access the trigger level control, press the HORIZONTAL Menu button, select Level, and use the LEVEL knob to change the value.
Positive-going edge Trigger level can be adjusted vertically Negative-going edge
Trigger slope can be positive or negative
Acquiring Data
When you acquire analog data, the oscilloscope converts it into a digital form. You can acquire data using three different acquisition modes. The timebase setting affects how rapidly data is acquired. Acquisition Modes There are three acquisition modes: Sample, Peak Detect, and Average.
Sample. In this acquisition mode, the oscilloscope samples the signal
in evenly spaced intervals to construct the waveform. This mode accurately represents analog signals most of the time.
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Basic Concepts
However, this mode does not acquire rapid variations in the analog signal that may occur between samples. This can result in aliasing (described on page 18) and may cause narrow pulses to be missed. In these cases, you should use the Peak Detect mode to acquire data.
Peak Detect. In this acquisition mode, the oscilloscope finds the
highest and lowest values of the input signal over a sample interval and uses these values to display the waveform. In this way, the oscilloscope can acquire and display narrow pulses, which may have otherwise been missed in Sample mode. Noise will appear to be higher in this mode.
Average. In this acquisition mode, the oscilloscope acquires several
waveforms, averages them, and displays the resulting waveform. You can use this mode to reduce random noise. Time Base The oscilloscope digitizes waveforms by acquiring the value of an input signal at discrete points. The time base allows you to control how often the values are digitized. To adjust the time base to a horizontal scale that suits your purpose, use the SEC/DIV knob.
Scaling and Positioning Waveforms
You can change the display of waveforms by adjusting their scale and position. When you change the scale, the waveform display will increase or decrease in size. When you change the position, the waveform will move up, down, right, or left.
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The channel reference indicator (located on the left of the graticule) identifies each waveform on the display. The indicator points to the ground level of the waveform record. Vertical Scale and Position You can change the vertical position of waveforms by moving them up or down on the display. To compare data, you can align a waveform above another or you can align waveforms on top of each other. You can change the vertical scale of a waveform. The waveform display will contract or expand about the ground level. Horizontal Scale and Position; Pretrigger Information You can adjust the Horizontal Position control to view waveform data before the trigger, after the trigger, or some of each. When you change the horizontal position of a waveform, you are actually changing the time between the trigger and the center of the display. (This appears to move the waveform to the right or left on the display.) For example, if you want to find the cause of a glitch in your test circuit, you might trigger on the glitch and make the pretrigger period large enough to capture data before the glitch. You can then analyze the pretrigger data and perhaps find the cause of the glitch. You change the horizontal scale of all the waveforms by using the SEC/DIV knob. For example, you might want to see just one cycle of a waveform to measure the overshoot on its rising edge.
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The oscilloscope shows the time per division in the scale readout. Since all active waveforms use the same time base, the oscilloscope only displays one value for all the active channels, except when you use a Window Zone.
Aliasing. Aliasing occurs when the oscilloscope does not sample the
signal fast enough to construct an accurate waveform record. When aliasing happens, you see a waveform with a frequency lower than the actual waveform being input or a waveform that is not stable even though the oscilloscope triggered.
Actual high-frequency waveform Apparent low-frequency waveform due to aliasing Sampled points
One way to check for aliasing is to slowly change the horizontal scale with the SEC/DIV knob. If the shape of the waveform changes drastically, you may have aliasing. 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 5 MHz would need to be sampled at 10 Megasamples per second or faster.
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The next table lists the time bases that you should use to avoid aliasing at various frequencies and the respective sample rate.
Samples per second 250.0 MS/s 100.0 MS/s 50.0 MS/s 25.0 MS/s 10.0 MS/s 5.0 MS/s 2.5 MS/s 1.0 MS/s 500.0 kS/s 250.0 kS/s 100.0 kS/s Maximum frequency 125.0 MHz* 50.0 MHz* 25.0 MHz* 12.5 MHz* 5.0 MHz* 2.5 MHz 1.25 MHz 500.0 kHz 250.0 kHz 125.0 kHz 50.0 kHz Samples per second 50.0 kS/s 25.0 kS/s 10.0 kS/s 5.0 kS/s 2.5 kS/s 1.0 kS/s 500.0 S/s 250.0 S/s 100.0 S/s 50.0 S/s Maximum frequency 25.0 kHz 12.5 kHz 5.0 kHz 2.5 kHz 1.25 kHz 500.0 Hz 250.0 Hz 125.0 Hz 50.0 Hz 25.0 Hz
Time base 1.0 ms 2.5 ms 5.0 ms 10.0 ms 25.0 ms 50.0 ms 100.0 ms 250.0 ms 500.0 ms 1.0 ms 2.5 ms
Time base 5.0 ms 10.0 ms 25.0 ms 50.0 ms 100.0 ms 250.0 ms 500.0 ms 1.0 s 2.5 s 5.0 s
* Bandwidth is not valid for the P2100 probe when the switch is set to 1X.
There are various ways to prevent aliasing: adjust the horizontal scale, push the AUTOSET button, or change the acquisition mode. NOTE. If aliasing occurs, change to the Peak Detect acquisition mode (described on page 16). This mode samples the highest and lowest values so that the oscilloscope can detect faster signals.
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Basic Concepts
Taking Measurements
The oscilloscope displays graphs of voltage versus time and can help you to measure the displayed waveform. There are several ways to take measurements. You can use the graticule, the cursors, or an automated measurement. Graticule This method allows you to make a quick, visual estimate. For example, you might look at a waveform amplitude and determine that it is a little more than 100 mV. You can take simple measurements by counting the 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 as follows: 5 divisions x 100 mV/division = 500 mV.
Cursor
Cursor
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Cursors This method allows you to take measurements by moving the cursors, which always appear in pairs, and reading their numeric values from the display readouts. There are two types of cursors: Voltage and Time. When you use cursors, be sure to set the Source to the waveform that you want to measure.
Voltage Cursors. Voltage cursors appear as horizontal lines on the
display and measure the vertical parameters.
Time Cursors. Time cursors appear as vertical lines on the display and
measure the horizontal parameters. Automated When you take automated measurements, the oscilloscope does all the calculating for you. Because these measurements use the waveform record points, they are more accurate than graticule or cursor measurements. Automated measurements use readouts to show measurement results. These readouts are updated periodically as the oscilloscope acquires new data.
Setting Up the Oscilloscope
You should become familiar with three functions that you will use often when operating your oscilloscope: Autoset, saving a setup, and recalling a setup. Included is a description of the default settings for normal operation of the oscilloscope.
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Using Autoset The Autoset function obtains a stable waveform display for you. It automatically adjusts the vertical and horizontal scaling, as well as the trigger coupling, type, position, slope, level, and mode settings. Saving a Setup By default, the oscilloscope saves the setup each time it is powered off. The oscilloscope automatically recalls this setup the next time it is powered on. NOTE. You should wait at least five seconds after your last change to the setup before you turn off the power. This ensures that the setup is saved properly. You can also permanently save up to five setups in the memory of the oscilloscope and overwrite setups as needed. Recalling a Setup The oscilloscope can recall any of the saved setups or the factory default setup. Defaults (Factory Setup) The oscilloscope is set up for normal operation when it is shipped from the factory. You can recall the factory default setup any time you want to operate the oscilloscope using or starting from the factory default settings.
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Operating Basics
The front panel is divided into easy to use functional areas. This section provides you with a quick overview of the controls and the information displayed on the screen. The next figure shows the front panels for a TDS 210 or TDS 220, and for a TDS 224 oscilloscope.
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Display Area
In addition to displaying waveforms, the display is filled with many details about the waveform and the instrument control settings.
1
2
Trig'd
3
4
Pos:-11.30ms
5
13
12
Ch1 500mV
Ch2 200mV
M 500ms
W 100ms
Ch1
750mV
11
10
9
8 7 6
1. Icon display shows acquisition mode. Sample mode Peak detect mode Average mode
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2. Trigger status indicates the following: Armed. The instrument is acquiring pretrigger data. All triggers are ignored in this state. R Ready. All pretrigger data has been acquired and the instrument is ready to accept a trigger. T Trig'd. The instrument has seen a trigger and is acquiring the posttrigger data. R Auto. The instrument is in auto mode and is acquiring waveforms in the absence of triggers. Scan. The instrument is acquiring and displaying waveform data continuously in scan mode. Stop. The instrument has stopped acquiring waveform data. 3. Marker shows horizontal trigger position. This is adjusted by the Horizontal Position control. 4. Readout shows the time difference between the center graticule and horizontal trigger position. Center screen equals zero. 5. Marker shows trigger level. 6. Readout shows numeric value of the trigger level. 7. Icon shows selected trigger type as follows: Edge trigger for the rising edge. Edge trigger for the falling edge. Video trigger for line sync. Video trigger for field sync.
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8. Readout shows trigger source used for triggering. 9. Readout shows window time base setting if it is in use. 10. Readout shows main time base setting. 11. Readouts show the vertical scale factors of the channels. 12. Display area shows on-line messages momentarily. 13. On-screen markers show the ground reference points of the displayed waveforms. No marker indicates the channel is not displayed.
Using the Menu System
The user interface of the TDS 200-series oscilloscopes was designed for easy access to specialized functions through the menu structure. When you press a menu button on the front panel, the associated menu title displays at the top right of the screen. There can be up to five menu boxes below the menu title. To the right of each menu box is a bezel button you can use to change the menu setting. There are four types of menu boxes you can use to change settings: Circular Lists, Action Buttons, Radio Buttons, and Page Selections. Circular List Menu Boxes A Circular List menu box appears with a title on top with the selected choice listed below in reverse video. For example, you can push the menu box button to cycle through the vertical coupling choices in the CH1 Menu.
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Action Button Menu Boxes An Action Button menu box displays the name of the action. For example, you can use the two lowest menu boxes in the DISPLAY menu to increase or decrease the contrast. Radio Button Menu Boxes Radio Button menu boxes are separated by dashed lines. The name of the selected menu box displays in reverse video. For example, you can use the top three menu boxes in the ACQUIRE menu to select an acquisition mode. Page Selection Menu Boxes A Page Selection menu box contains two menus for a single button on the front panel with the selected menu displayed in reverse video. Each time you press the top menu box button to toggle between the two menus, the menu boxes below also change. For example, when you press the SAVE/RECALL front panel button, the top Page Selection menu contains the names of two menus: Setups and Waveforms. When you select the Setups menu, you can use the remaining menu boxes to save or recall setups. When you select the Waveforms menu, you can use the remaining menu boxes to save or recall waveforms. The SAVE/RECALL, MEASURE, and TRIGGER front panel buttons display Page Selection menu boxes.
Circular List Action Button Radio Button Page Selection
or
or
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Waveform Displays
Obtaining a waveform display is dependent on many instrument settings. Once you obtain a waveform, you can take your measurements. But the appearance of these waveforms also provides key information about the waveform. Depending on the type, waveforms will be displayed in three different styles: black, gray, and broken.
1
2
3
1. A solid black waveform indicates a live waveform display. The waveform remains black when the acquisition is stopped if no controls are changed that make the display accuracy uncertain. Changing the vertical and horizontal controls is allowed on stopped acquisitions.
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2. Reference waveforms and waveforms with persistence applied appear gray. 3. A broken line appearance indicates the waveform display accuracy is uncertain. This is the result of stopping the acquisition and then changing a control setting that the instrument cannot modify the displayed waveform to match. For example, changing the trigger controls on a stopped acquisition causes a broken-line waveform.
Vertical Controls
TDS 210 and TDS 220
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TDS 224
CH 1, 2, 3 & 4 and CURSOR 1 & 2 POSITION. Positions the waveform
vertically. When cursors are turned on and the cursor menu is displayed, these knobs position the cursors.
CH 1, CH 2, CH 3 & CH 4 MENU. Displays the channel input menu selections and toggles the channel display on and off. VOLTS/DIV (CH1, CH 2, CH 3 & CH 4). Selects calibrated scale factors. MATH MENU. Displays waveform math operations menu and can also
be used to toggle the math waveform on and off.
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Horizontal Controls
TDS 224
TDS 210 and TDS 220
POSITION. Adjusts the horizontal position of all channels and math
waveforms. The resolution of this control varies with the time base. NOTE. To make a large adjustment to the horizontal position, change the SEC/DIV to 50 ms, change the horizontal position, and then change the SEC/DIV back to the previous value.
HORIZONTAL MENU. Displays the horizontal menu.
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SEC/DIV. Selects the horizontal time/div (scale factor) for the main or the window time base. When Window Zone is enabled, it changes the width of the window zone by changing the window time base. Refer to page 75 for details about creating and using the Window Zone.
Trigger Controls
TDS 224
TDS 210 and TDS 220
LEVEL and HOLDOFF. This control has a dual purpose. As an edge
trigger level control, it sets the amplitude level the signal must cross to cause an acquisition. As a holdoff control, it sets the amount of time before another trigger event can be accepted. Refer to Holdoff on page 13 for more information.
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TRIGGER MENU. Displays the trigger menu. SET LEVEL TO 50%. The trigger level is set to the vertical midpoint
between the peaks of the trigger signal.
FORCE TRIGGER. Starts an acquisition regardless of an adequate
trigger signal. This button has no effect if the acquisition is already stopped.
TRIGGER VIEW. Displays the trigger waveform in place of the channel
waveform while the TRIGGER VIEW button is held down. You can use this to see how the trigger settings affect the trigger signal, such as trigger coupling.
Menu and Control Buttons
TDS 210 and TDS 220
TDS 224
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SAVE/RECALL. Displays the save/recall menu for setups and waveforms. MEASURE. Displays the automated measurements menu. ACQUIRE. Displays the acquisition menu. DISPLAY. Displays the display menu. CURSOR. Displays the cursor menu. Vertical Position controls adjust
cursor position while displaying the cursor menu and the cursors are turned on. Cursors remain displayed (unless turned off) after leaving the cursor menu but are not adjustable.
UTILITY. Displays the utility menus. AUTOSET. Automatically sets the instrument controls to produce a
usable display of the input signal.
HARDCOPY. Starts print operations. An extension module with a
Centronics, RS-232, or GPIB port is required. Refer to Optional Accessories on page 103.
RUN/STOP. Starts and stops waveform acquisition.
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Connectors
TDS 210 and TDS 220
TDS 224
PROBE COMP. Voltage probe compensation output and ground. Use this to electrically match the probe to the input circuit. Refer to page 6.
The probe compensation ground and BNC shields are connected to earth ground. Do not connect a voltage source to these ground terminals.
CH 1, CH 2, CH 3 & CH 4. Input connectors for waveform display. EXT TRIG. Input connector for an external trigger source. Use the trigger menu to select the trigger source.
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Application Examples
This section presents a series of application examples. These simplified examples highlight the features of the oscilloscope and give you ideas for using it to solve your own test problems. H Taking simple measurements Using Autoset Using the Measure menu to take automatic measurements Measuring two signals and calculating gain H Taking cursor measurements Measuring pulse width Measuring rise time Measuring ring frequency and ring amplitude H Analyzing signal detail Looking at a noisy signal Using the average function to separate a signal from noise H Triggering on a video signal Triggering on video fields and video lines Using the window function to see waveform details Triggering on odd or even video fields H Analyzing a differential communication signal Using math functions H Viewing impedance changes in a network Using XY mode Using persistence
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Application Examples
Taking Simple Measurements
You need to see a signal in a circuit, but you do not know the amplitude or frequency of the signal. You want to quickly display the signal and measure the frequency, period, and peak-to-peak amplitude.
CH 1
Using Autoset To quickly display a signal, do these steps: 1. Set the Probe menu attenuation to 10X. Set the switch to 10X on the P2100 probe. 2. Connect the channel 1 probe to the signal. 3. Push the AUTOSET button. The oscilloscope sets the vertical, horizontal, and trigger controls automatically. If you want to optimize the display of the waveform, you can manually adjust these controls. When you use more than one channel, the autoset function sets the vertical controls for each channel and uses the lowest-numbered active channel to set the horizontal and trigger controls.
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Taking Automatic Measurements The oscilloscope can take automatic measurements of most displayed signals. To measure signal frequency, period, and peak-to-peak amplitude, do these steps: 1. Push the MEASURE button to see the Measure menu. 2. Push the top menu box button to select Source. 3. Select CH1 for the first three measurements. 4. Push the top menu box button to select Type. 5. Push the first CH1 menu box button to select Freq. 6. Push the second CH1 menu box button to select Period. 7. Push the third CH1 menu box button to select Pk-Pk. The frequency, period, and peak-to-peak measurements are shown in the menu and are updated periodically.
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Measuring Two Signals You are testing a piece of equipment and need to measure the gain of the audio amplifier. You have an audio generator that can inject a test signal at the amplifier input. Connect two oscilloscope channels to the amplifier input and output as shown. Measure both signal levels and use the measurements to calculate the gain.
CH 1 CH 2
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To activate and display the signals connected to channel 1 and to channel 2, do these steps: 1. If the channels are not displayed, push the CH 1 MENU and then CH 2 MENU buttons. 2. Push the AUTOSET button. To select measurements for the two channels, do these steps: 1. Select the source channels. a. Push the MEASURE button to see the Measure menu. b. Push the top menu box button to select Source. c. Push the second menu box button to select CH1. d. Push the third menu box button to select CH2. 2. Select the type of measurement displayed for each channel. a. Push the top menu box button to select Type. b. Push the CH1 menu box button to select Pk-Pk. c. Push the CH2 menu box button to select Pk-Pk. 3. Read the peak-to-peak amplitudes for channel 1 and channel 2 in the menu display. 4. Calculate the amplifier gain using the following equations: output amplitude input amplitude log(Gain)
Gain +
Gain (dB) + 20
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Application Examples
Taking Cursor Measurements
You can use the cursors to quickly take time and voltage measurements on a waveform. Measuring Pulse Width You are analyzing a pulse waveform, and you want to know the width of the pulse. To measure the width of a pulse using the time cursors, do these steps: 1. Push the CURSOR button to see the Cursor menu. 2. Push the top menu box button to select Time. 3. Push the Source menu box button to select CH1. 4. Use the CURSOR 1 knob to place a cursor on the rising edge of the pulse. 5. Use the CURSOR 2 knob to place the remaining cursor on the falling edge of the pulse. You can see the following measurements in the Cursor menu: H The time at Cursor 1, relative to the trigger. H The time at Cursor 2, relative to the trigger. H The delta time, which is the pulse width measurement.
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NOTE. The TDS2MM extension module provides pulse width as an automatic measurement.
Measuring Rise Time After measuring the pulse width, you decide that you need to check the rise time of the pulse. Typically, you measure rise time between the 10% and 90% portion of the waveform. To measure the rise time, do these steps: 1. Adjust the SEC/DIV knob to display the rising edge of the waveform. 2. Adjust the VOLTS/DIV knob to set the waveform amplitude to about five divisions. 3. Push the CH 1 MENU button to see the CH1 menu if it is not displayed. 4. Push the Volts/Div button to select Fine.
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Application Examples
5. Adjust the VOLTS/DIV knob to set the waveform amplitude to exactly five divisions. 6. Use the VERTICAL POSITION knob to center the waveform; position the baseline of the waveform 2.5 divisions below the center graticule. 7. Push the CURSOR button to see the Cursor menu. 8. Push the top menu box button to set the type to Time. 9. Use the CURSOR 1 knob to place the cursor at the point where the waveform crosses the second graticule line below center screen. This is the 10% point on the waveform. 10. Use the CURSOR 2 knob to place the second cursor at the point where the waveform crosses the second graticule line above center screen. This is the 90% point on the waveform. 11. The delta readout in the cursor menu is the rise time of the waveform.
5 divisions
NOTE. The TDS2MM extension module provides rise time as an automatic measurement.
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Application Examples
Measuring Ring Frequency To measure the ring frequency at the rising edge of a signal, do these steps: 1. Push the CURSOR button to see the Cursor menu. 2. Push the top menu box button to select Time. 3. Use the CURSOR 1 knob to place a cursor on the first peak of the ring. 4. Use the CURSOR 2 knob to place a cursor on the second peak of the ring. You can see the delta time and frequency (the measured ring frequency) in the Cursor menu.
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Measuring Ring Amplitude You measured the ring frequency in the previous example. Now you want to measure the amplitude of the ringing. To measure the amplitude, do these steps: 1. Push the CURSOR button to see the Cursor menu. 2. Push the top menu box button to select Voltage. 3. Use the CURSOR 1 knob to place a cursor on the highest peak of the ring. 4. Use the CURSOR 2 knob to place a cursor on the lowest point of the ring. You can see the following measurements in the cursor menu: H The delta voltage (peak-to-peak voltage of the ringing) H The voltage at Cursor 1 H The voltage at Cursor 2
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Application Examples
Analyzing Signal Detail
You have a noisy signal displayed on the oscilloscope and you need to know more about it. You suspect that the signal contains much more detail than you can now see in the display.
Looking at a Noisy Signal The signal appears noisy and you suspect that noise is causing problems in your circuit. To better analyze the noise, do these steps: 1. Push the ACQUIRE button to see the Acquire menu. 2. Push the Peak detect button. 3. If necessary, push the DISPLAY button to see the Display menu. Use the Contrast Increase and Contrast Decrease menu box buttons to adjust the contrast to see the noise more easily. Peak detect emphasizes noise spikes and glitches in your signal, especially when the time base is set to a slow setting.
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Application Examples
Separating the Signal from Noise Now you want to analyze the signal shape and ignore the noise. To reduce random noise in the oscilloscope display, do these steps: 1. Push the ACQUIRE button to see the Acquire menu. 2. Push the Average menu box button. 3. Push the Averages menu box button to see the effects of varying the number of running averages on the waveform display. Averaging reduces random noise and makes it easier to see detail in a signal. In the example below, a ring shows on the rising and falling edges of the signal when the noise is removed.
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Application Examples
Capturing a Single-Shot Signal
The reliability of a reed relay in a piece of equipment has been poor and you need to investigate the problem. You suspect that the relay contacts arc when the relay opens. The fastest you can open and close the relay is about once per minute so you need to capture the voltage across the relay as a single-shot acquisition. To set up for a single-shot acquisition, do these steps: 1. Adjust the vertical VOLTS/DIV and horizontal SEC/DIV to appropriate ranges for the signal you expect to see. 2. Push the ACQUIRE button to see the Acquire menu. 3. Push the Peak detect button. 4. Push the TRIGGER MENU button to see the Trigger menu. 5. Push the Mode button to select Single (single sequence). 6. Push the Slope button to select Rising. 7. Use the LEVEL knob to adjust the trigger level to a voltage midway between the open and closed voltages of the relay. 8. If the readout at the top of the screen does not display Armed or Ready, then push the RUN/STOP button to start the acquisition. When the relay opens, the oscilloscope is triggered and captures the event.
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Optimizing the Acquisition The initial acquisition shows the relay contact beginning to open at the trigger point. This is followed by a large spike that indicates contact bounce and inductance in the circuit. The inductance can cause contact arcing and premature relay failure. You can adjust the vertical, horizontal, and trigger controls to optimize the settings before the next single-shot event is captured. When the next acquisition is captured with the new settings, you can see more detail about the relay contact opening. You can now see that the contact bounces several times as it opens.
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Measuring Propagation Delay
You suspect that the memory timing in a microprocessor circuit is marginal. Set up the oscilloscope to measure the propagation delay between the chip-select signal and the data output of the memory device.
Data
CS
CH 1 CH 2
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Application Examples
To set up to measure propagation delay, do these steps: 1. If the channels are not displayed, push the CH 1 MENU and then CH 2 MENU buttons. 2. Push AUTOSET to trigger a stable display. 3. Adjust the horizontal and vertical controls to optimize the display. 4. Push the CURSOR button to see the Cursor menu. 5. Push the top menu box button to select Time. 6. Push the Source menu box button to select CH1. 7. Use the CURSOR 1 knob to place the cursor on the active edge of the chip-select signal. 8. Use the CURSOR 2 knob to place the second cursor on the data output transition. 9. Read the propagation delay in the Delta readout in the cursor menu.
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Application Examples
Triggering on a Video Signal
You are testing the video circuit in a piece of medical equipment and need to display the video output signal. The video output is an NTSC standard signal. Use the video trigger to obtain a stable display.
75 W terminator
CH 1
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Triggering on Video Fields To trigger on the video fields, do these steps: 1. Push the TRIGGER MENU button to see the Trigger menu. 2. Push the top menu box button to select Video. 3. Push the Sync menu box button to select Field. 4. Adjust the horizontal SEC/DIV knob to see a complete field across the screen. 5. Push the HORIZONTAL MENU button to see the Main menu. 6. Push the Trig knob menu box button to select Holdoff. 7. Adjust the HOLDOFF knob to an appropriate period. You can use about 21 ms for NTSC (and PAL) video. Triggering on Video Lines You can also look at the video lines in the field. To trigger on the lines, do these steps: 1. Push the TRIGGER MENU button to see the Trigger menu. 2. Push the top menu box button to select Video. 3. Push the Sync menu box button to select Line. 4. Adjust the horizontal SEC/DIV knob to see a complete video line across the screen.
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Incoming video signal 75 W terminator
CH 1
Using the Window Function to See Waveform Details You can use the window function to examine a specific portion of a waveform without changing the main display.
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If you want to view the color burst in the previous waveform in more detail without changing the main display, do these steps: 1. Push the HORIZONTAL MENU button to see the Horizontal menu and select Main. 2. Adjust the horizontal SEC/DIV knob to select 50 ms. 3. Push the Trig knob menu box button to select Holdoff. 4. Adjust the HOLDOFF knob to 61 ms. 5. Adjust the horizontal SEC/DIV knob until you see a whole line. 6. Push the Window Zone menu box button. 7. Adjust the SEC/DIV knob to set the width of the window (area to be expanded). 8. Adjust the HORIZONTAL POSITION knob to position the window around the portion of the waveform you want to expand.
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Application Examples
9. Push the Window button to see the expanded portion of the waveform. 10. Adjust the SEC/DIV knob to optimize viewing the expanded waveform. To switch between the Main and Window views, push the Main or Window menu box button in the HORIZONTAL MENU.
Triggering on Odd or Even Video Fields Your oscilloscope will trigger on both odd and even video fields, and make the data difficult to view because the line details are a half line apart. To remedy this, you can set the holdoff period to lock on just the odd or even field, which produces a stable display. For example, the field rate for NTSC video is 60 Hz. For stable triggering, you should set the holdoff period to at least the field rate (16.7 ms), but not to more than twice the field rate (33 ms).
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Application Examples
To trigger on only an odd or even video field, do these steps: 1. If channel 1 is not displayed, push the CH 1 MENU button. 2. Use the VERTICAL POSITION knob to place the waveform on the middle graticule line (position 0). 3. Adjust the VERTICAL VOLTS/DIV knob to 500 mV. 4. Push the Coupling menu box button to select DC. 5. Push the Probe menu box button to select 1X. 6. Push the TRIGGER MENU button to see the Trigger menu. 7. Push the top menu box button to select VIDEO. 8. Push the Polarity menu box button to select Normal. 9. Push the Source menu box button to select CH1. 10. Push the Sync menu box button to select Field. 11. Push the ACQUIRE button to see the Acquire menu. 12. Set SEC/DIV to 10 ms. 13. Adjust the HORIZONTAL POSITION knob to about 1.5 ms. 14. Push the HORIZONTAL MENU button to see the Main menu.
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15. Push the Trig knob menu box button to select Holdoff. 16. Adjust the HOLDOFF knob to 21 ms for NTSC and PAL video. NOTE. To make a large adjustment to the holdoff period, adjust the SEC/DIV knob to 50 ms, adjust the HOLDOFF knob to 21 ms, and readjust the SEC/DIV back to the previous value. Now the oscilloscope only triggers on an odd or an even field (but not both), and the line information is stable.
With 500 ns of holdoff time, you cannot see any line information because the alternating fields overlap
With 21 ms of holdoff time you can easily see one clear line
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Analyzing a Differential Communication Signal
You are having intermittent problems with a serial data communication link, and you suspect poor signal quality. Set up the oscilloscope to show you a snapshot of the serial data stream so you can verify the signal levels and transition times. Because this is a differential signal, you use the math function of the oscilloscope to view a better representation of the waveform.
CH 1 CH 2
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To activate the differential signals connected to channel 1 and channel 2, do these steps: 1. Set the Probe menu attenuation to 10X. Set the switch to 10X on the P2100 probes. 2. If the channels are not displayed, push the CH 1 MENU and then CH 2 MENU buttons. 3. Push the AUTOSET button. 4. Push the MATH button to see the Math menu. TDS 210 and TDS 220 (Firmware V 2.00 and Above), and TDS 224 (All Versions) Oscilloscopes Do these steps: 1. Push the Operation menu box button to select . 2. Push the CH1CH2 menu box button to display a new waveform that is the d