Tektronix TDS 540, TDS 520 User Manual

0 (0)

User Manual

TDS 520 & 540

Digitizing Oscilloscopes

070-8317-01

This document supports Version 2 firmware.

Please check for change information at the rear of this manual.

First Printing: March 1992

Last Revised: November 1992

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.

Printed in the U.S.A.

Tektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070±1000

TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.

Microsoft is a registered trademark of Microsoft Corporation

IBM is a registered trademark of International Business Machines

GPIB-PCII and GPIB-PCIIA are registered trademarks of National Instruments Corporation

Epson is a registered trademark of Epson America, Inc.

Interleaf is a trademark of Interleaf, Inc.

PostScript is a registered trademark of Adobe Systems Incorporated

WARRANTY

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. If a 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; c) to repair any damage or malfunction caused by the use of non-Tektronix supplies; or d) 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 IN LIEU OF ANY OTHER WARRANTIES, EXPRESS 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.

This apparatus has been designed and tested in accordance with IEC Publication 348, Safety Requirements for Electronic Measuring Apparatus, and has been supplied in a safe condition. This manual contains some information and warnings which have to be followed by the user to ensure safe operation and to retain the apparatus in safe condition.

The apparatus has been designed for indoor use. It may occasionally be subjected to temperatures between +5_ C and ±10_ C without degradation of its safety.

Welcome

Related Manuals

This is the User Manual for the TDS 520 and TDS 540 Digitizing Oscilloscopes.

If you are a new user, try the Tutorial section to become familiar with the operation of your digitizing oscilloscope.

The Concepts section covers basic principles of the operation of the oscilloscope. These articles help you understand why your instrument works the way it does.

Use the In Detail section to learn how to perform specific tasks. See page 3-1 for a complete list of tasks covered in that section.

The Appendices provide an option and accessories listing, product specification, and other useful information.

The following documents are related to the use or service of the digitizing oscilloscope.

HThe TDS Family Programmer Manual (Tektronix part number 070-8318-03) describes using a computer to control the digitizing oscilloscope through the GPIB interface.

HThe TDS 520 & 540 Reference (Tektronix part number 070-8316-01) gives you a quick overview of how to operate your digitizing oscilloscope.

HThe TDS Family Option 2F Instruction Manual (Tektronix part number 070-8582-00) describes use of the Advanced DSP Math option (for TDS oscilloscopes equipped with that option only).

HThe TDS Family Option 13 Instruction Manual (Tektronix part number 070-8567-00) describes using the optional Centronicsr and RS-232 interfaces for obtaining hardcopy (for TDS oscilloscopes equipped with that option only).

HThe TDS 520 & TDS 540 Performance Verification (Tektronix part number 070-8603-00) tells how to verify the performance of the digitizing oscilloscope.

HThe TDS 520 Service Manual (Tektronix part number 070-8312-01) and the TDS 540 Service Manual (070-8314-01) provide information for maintaining and servicing your digitizing oscilloscope to the module level.

TDS 520 & TDS 540 User Manual

Conventions

In the Tutorial and In Detail sections, you will find various procedures which contain steps of instructions for you to perform. To keep those instructions clear and consistent, this manual uses the following conventions:

HNames of front panel controls and menu labels appear in boldface print.

HNames 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.

HInstruction steps are numbered. The number is omitted if there is only one step.

HWhen 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) Bandwidth (main) 100 MHz (side).

Using the convention just described results in instructions that are graphically 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

HSometimes 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

Contents

Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	v
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	vi
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	viii

Tutorial

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-1
Example 1: Displaying a Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-2
Example 2: Multiple Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-8
Example 3: Automated Measurements . . . . . . . . . . . . . . . . . . . . . . . .	1-12
Example 4: Saving Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-18

Concepts

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Scaling and Positioning Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

In Detail

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-1
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-2
Acquisition Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-11
Autoset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-18
Cursor Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-20
Delayed Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-25
Display Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-31
Edge Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-36
Hardcopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-40

TDS 520 & TDS 540 User Manual

Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-48
Horizontal Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-49
Limit Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-53
Logic Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-58
Measurement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-66
Probe Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-77
Probe Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-84
Probe Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-90
Probe Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-92
Pulse Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-99
Remote Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-106
Saving and Recalling Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-110
Saving and Recalling Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-112
Selecting Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-115
Signal Path Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-117
Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-119
Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-120
Vertical Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-124
Waveform Math . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-127
Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-130

Appendices

Appendix A: Options and Accessories . . . . . . . . . . . . . . . . . . . . . . . .	A-1
Appendix B: Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	A-9
Appendix C: Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	A-25
Appendix D: Packaging for Shipment . . . . . . . . . . . . . . . . . . . . . . . . .	A-39
Appendix E: Factory Initialization Settings . . . . . . . . . . . . . . . . . . . .	A-41

Glossary & Index

Change Information

Contents

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:

H500 MHz maximum analog bandwidth.

H1 Gigasample/second maximum digitizing rate (TDS 540);

500 Megasamples/second maximum digitizing rate (TDS 520).

HFour-channel acquisitionÐthe TDS 540 offers four full-featured channels; the TDS 520 offers two full-featured channels and two channels with limited vertical scale selections: 100 mV, 1 V, and 10 V.

HWaveform MathÐInvert a single waveform and add, subtract, and multiply two waveforms. On instruments equipped with option 2F, 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.

HEight-bit digitizers.

HUp to 15,000-point record length per channel (50,000-point optional).

HFull GPIB software programmability. GPIB hardcopy output. On instruments equipped with option 13, hardcopy output using the RS-232 or Centronics ports.

HComplete measurement and documentation capability.

HIntuitive graphic icon operation blended with the familiarity of traditional

horizontal and vertical knobs.

HOn-line help at the touch of a button.

TDS 520 & TDS 540 User Manual

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.

Symbols and Terms

These two terms appear in manuals:

H statements identify conditions or practices that could result in

damage to the equipment or other property.

H statements identify conditions or practices that could result in

personal injury or loss of life.

These two terms appear on equipment:

HCAUTION indicates a personal injury hazard not immediately accessible as one reads the marking or a hazard to property including the equipment itself.

HDANGER 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	Protective	ATTENTION
High Voltage	ground (earth)	Refer to
	terminal	manual

Safety

Specific Precautions Observe all of these precautions to ensure your personal safety and to prevent damage to either the digitizing oscilloscope or equipment connected to it.

Power Source

The digitizing oscilloscope is intended to operate from a power source that will not apply more than 250 Vrms between the supply conductors or between 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 oscilloscope.

Without the protective ground connection, all parts of the digitizing oscilloscope 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 discharges or arcing components. Do not operate the digitizing oscilloscope in an atmosphere of explosive gases.

TDS 520 & TDS 540 User Manual

vii

Start Up

Operation

Before you use the digitizing oscilloscope, ensure that it is properly installed and powered on.

To properly install and power on the digitizing oscilloscope, do the following:

Installation

1.Be sure you have the appropriate operating environment. Specifications for temperature, relative humidity, altitude, vibrations, and emissions are included in Appendix B: Specification at the rear of this manual.

2.Leave space for cooling. Do this by verifying that the air intake and exhaust holes on the sides of the cabinet (where the fan operates) are free of any airflow obstructions. Leave at least 2 inches (5.1 cm) free on each side.

WARNING

To avoid electrical shock, be sure that the power cord is disconnected before checking the fuse.

3.Check the fuse to be sure it is the proper type and rating (Figure i). You can use either of two fuses. Each fuse requires its own cap (see Table i). The digitizing oscilloscope is shipped with the UL approved fuse installed.

4.Check that you have the proper electrical connections. The digitizing

oscilloscope requires 90 to 250 VACrms, continuous range, 47 Hz to 63 Hz, and may require up to 300 W.

5.Connect the proper power cord from the rear-panel power connector (Figure i) to the power system.

viii

Start Up

Power Connector

Principal Power Switch

Fuse

Figure i: Rear Panel Controls Used in Start Up

Table i: Fuse and Fuse Cap Part Numbers

Fuse	Fuse Part	Fuse Cap Part
	Number	Number

.25 inch 1.25 inch (UL 198.6, 3AG):	159±0013±00	200±2264±00
6 A FAST, 250 V.

5 mm 20 mm (IEC 127): 5 A (T),	159±0210±00	200±2265±00
250 V.

Power On

1.Check that the rear-panel principal power switch is on (Figure i). 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 (Figure ii).

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.

Once the digitizing oscilloscope is installed, you can leave the principal power switch on and use the ON/STBY button as the power switch.

TDS 520 & TDS 540 User Manual

ON/STBY Button

Figure ii: ON/STBY Button

Self Test

The digitizing oscilloscope automatically performs power-on 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.)

Check the self test results.

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 serviced.

Power Off

Press the ON/STBY switch to turn off the oscilloscope.

Before You Begin

Now that you have set up your oscilloscope for operation, you should know about two features that help to ensure maximum accuracy for your most critical measurements, Signal Path Compensation and Probe Cal.

Signal Path Compensation (SPC) lets you compensate your oscilloscope for the current ambient temperature, helping to ensure maximum possible accuracy for your most critical measurements. See Signal Path Compensation on page 3-117 for a description of and operating information on this key feature.

Start Up

Probe Cal lets you compensate any channel of your oscilloscope for the effect of the probe on gain accuracy and offset accuracy. Like SPC, Probe Cal helps ensure maximum possible accuracy for your most critical measurements. See Probe Cal on page 3-84 for a description of and operating information on this feature.

TDS 520 & TDS 540 User Manual

xii

Start Up

Tutorial

Overview

This section contains four examples that show you how to operate the basic functions of the digitizing oscilloscope. Use the At a Glance section (starting on page 3-2) to help you locate the correct knobs, buttons, and menus.

HExample 1 teaches you how to reset the digitizing oscilloscope, display and adjust waveforms, and use the autoset function.

HExample 2 explains how to add, control, and delete multiple waveforms.

HExample 3 introduces you to the automated measurement system.

HExample 4 discusses saving and recalling the digitizing oscilloscope setups.

Before you perform these examples, read Conventions on page ii. If you decide to skip this tutorial, use the Concepts and In Detail sections to learn about the digitizing oscilloscope arrangement and specific functions.

Setting Up for the

All the examples use the same setup. Once you perform this setup, you do

Examples

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 (Figure 1-1).

Figure 1-1: Connecting a Probe for the Examples

TDS 620 & 640 User Manual

1 1

Example 1: Displaying a Waveform

Resetting the

Digitizing

Oscilloscope

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 ªstart freshº with known default settings.

1.Press the save/recall SETUP button to display the Setup menu (Figure 1-2).

SETUP Button

Figure 1-2: SETUP Button Location

The digitizing oscilloscope displays main menus along the bottom of the screen. Figure 1-3 shows the Setup main menu.

OK Confirm Factory Init

Menu Item and Button

Recall Factory Setup

Menu Item and Button

Figure 1-3: The Displayed Setup Menu

1 2	Section Name (Nm:Sect)

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 1-3).

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 SETUP 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 1-4) to be sure the oscilloscope triggers on the input signal.

SET LEVEL TO 50% Button

Figure 1-4: Trigger Controls

TDS 620 & 640 User Manual

1 3

Example 1: Displaying a Waveform

Display Elements	Figure 1-5 shows the display that results from the instrument reset. There are
	several important points to observe:
	H The trigger level bar shows that the waveform is triggered at a level near
	50% of its amplitude (from step 4).
	H The trigger position indicator shows that the trigger position of the wave-
	form is located at the horizontal center of the graticule.
	H 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.
	H 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.
	H The time base readout shows that the main time base is set to a horizon-
	tal scale of 500 ms/div.
	H 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

Running: 100kS/s

Sample

Figure 1-5: The Display After Factory Initialization

Right now, the channel, time base, and trigger readouts appear in the graticule 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.

1 4	Section Name (Nm:Sect)

Adjusting the

Waveform Display

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.

Figure 1-6 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 1-6: The VERTICAL and HORIZONTAL Controls

Using Autoset

2.Turn the vertical POSITION knob first one direction, then the other. Observe the change in the displayed waveform. Then return the waveform 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 ms/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 displayed may not be scaled and triggered correctly. Use the autoset function and you should quickly get a meaningful display.

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 oscilloscope.

TDS 620 & 640 User Manual

1 5

Example 1: Displaying a Waveform

1.To create an unstable display, slowly turn the trigger MAIN LEVEL knob (see Figure 1-7) 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 1-8) and observe the stable waveform display.

MAIN LEVEL Knob

Figure 1-7: TRIGGER Controls

AUTOSET Button

Figure 1-8: AUTOSET Button Location

Figure 1-9 shows the display after pressing AUTOSET. If necessary, you can adjust the waveform now by using the knobs discussed earlier in this example.

1 6	Section Name (Nm:Sect)

Example 1: Displaying a Waveform

Figure 1-9: The Display After Pressing Autoset

NOTE

If the corners on your displayed signal look rounded or pointed (see Figure 1-10), then you may need to compensate your probe. The Probe Compensation section on page 3-90 explains how to do that.

Figure 1-10: Display Signals Requiring Probe Compensation

TDS 620 & 640 User Manual

1 7

Example 2: Multiple Waveforms

In this example you learn how to display and control more than one waveform at a time.

Adding a Waveform

The VERTICAL section of the front panel contains the channel selection

buttons. On the TDS 640 Digitizing Oscilloscope, these are CH 1, CH 2,

CH 3, CH 4, and MORE (Figure 1-11); on the TDS 620, they are CH 1, CH 2,

AUX 1, AUX 2, and MORE.

Figure 1-11: The Channel Buttons and Lights (TDS 540 Shown)

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 adds a waveform to the display.

1.If you are not continuing from the previous example, follow the instructions on page 1-1 under the heading ªSetting Up for the Examples.º

1 8	Section Name (Nm:Sect)

Example 2: Multiple Waveforms

2.Press SETUP Recall Factory Setup (main) OK Confirm Factory Init (side).

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:

HThe channel readout on the display now shows the settings for both

Ch1 and Ch2.

HThere are two channel indicators at the left edge of the graticule. Right now, they overlap.

HThe 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.

HThe 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 waveform up on the graticule. You will notice that the channel reference indicator 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 1-12). 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 W (side) to toggle the selection to 50 W. That changes the input coupling of channel 2 from 1 MW to 50 W. The channel readout for channel 2 (near the bottom of the graticule) now shows an W indicator.

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Example 2: Multiple Waveforms

Running: 100kS/s

Sample

Ch2 Reference Indicator

Side Menu Title

Changing Controls to Another Channel

Figure 1-12: 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.

1.Press CH 1.

Observe that now the side menu title shows Ch1 (Figure 1-13), and that the light above CH 1 is lighted. The highlighted menu item in the side menu has changed from the 50 W channel 2 setting to the 1 MW impedance setting of channel 1.

2.Press CH 2 W (side) to toggle the selection to 1 MW. That returns the coupling impedance of channel 2 to its initial state.

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Example 2: Multiple Waveforms

Running: 100kS/s

Sample

Side Menu Title

Removing a

Waveform

Figure 1-13: The Menus After Changing Channels

Pressing the WAVEFORM OFF button removes the waveform for the currently selected channel. If the waveform you want to remove is not already selected, select that channel using the channel (CH) button.

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.

TDS 620 & 640 User Manual

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Example 3: AutomatedMeasurements

Displaying

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.

1.If you are not continuing from the previous example, follow the instructions on page 1-1 under the heading ªSetting Up for the Examples.º

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 1-14).

Figure 1-14: Measure Main Menu and Select Measurement Side Menu

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