Tektronix 524A - Manual

EC Declaration of Conformity We Tektronix Holland N.V.Marktweg 73A8444 AB HeerenveenThe Netherlands declare under sole responsibility that the TDS 520A, 524A, 540A, & 544A Digitizing Oscilloscopes meet the intent of Directive 89/336/EEC for Electromagnetic Compatibility. Compliance was demonstra...

TDS 620A, 640A, & 644A User Manual i Welcome This is the User Manual for the TDS Family Digitizing Oscilloscopes. The Getting Started section familiarizes you with the operation of the digitizing oscilloscope. Operating Basics covers basic principles of the operation of the oscilloscope.These ar...

Welcome Welcome ii In the Getting Started and Reference sections, you will find various proce- dures which contain steps of instructions for you to perform. To keep thoseinstructions clear and consistent, this manual uses the following conventions: H In procedures, names of front panel controls and ...

TDS 520A, 524A, 540A, & 544A User Manual iii Table of Contents Safety v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Getting Started Product Description 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

Table of Contents Contents i File System (Optional on TDS 520A & TDS 540A) 3-55 . . . . . . . . . . . . . . Hardcopy 3-59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Help 3-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

TDS 620A, 640A, & 644A User Manual v Safety Please take a moment to review these safety precautions. They are providedfor your protection and to prevent damage to the digitizing oscilloscope. Thissafety information applies to all operators and service personnel. These two terms appear in manuals...

Safety Safety vi Observe all of these precautions to ensure your personal safety and to pre-vent damage to either the digitizing oscilloscope or equipment connected to it. Power Source The digitizing oscilloscope is intended to operate from a power source that willnot apply more than 250 V RMS betwe...

TDS 520A, 524A, 540A, & 544A User Manual 1Ć1 Product Description Your Tektronix digitizing oscilloscope is a superb tool for acquiring, displaying,and measuring waveforms. Its performance addresses the needs of bothbenchtop lab and portable applications with the following features: H 500 MHz max...

TDS 620A, 640A, & 644A User Manual 1Ć3 Start Up Before you use the digitizing oscilloscope, ensure that it is properly installedand powered on. To ensure maximum accuracy for your most critical measurements, youshould know about signal path compensation. Signal Path Compensation Be sure you comp...

Start Up Getting Started 1Ć4 4. Check that you have the proper electrical connections. The digitizingoscilloscope requires 90 to 250 VAC RMS , 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 (seeFigure 1-1) to the po...

Start Up TDS 620A, 640A, & 644A User Manual 1Ć5 Once the digitizing oscilloscope is installed, it is typical to leave the princi-pal power switch on and use the ON/STBY button as the power switch. ON/STBY Button Figure 1-2: ON/STBY Button Self Test Check the self test results. The digitizing osc...

Getting Started 1Ć6 Setting Up for the Examples All the examples use the same setup. Once you perform this setup, you donot have to change the signal connections for any of the other examples. Remove all probes and signal inputs from the input BNC connectors along thelower right of the front panel. ...

TDS 620A, 640A, & 644A User Manual 1Ć7 Example 1: Displaying a Waveform In this first example you learn about resetting the digitizing oscilloscope,displaying and adjusting a waveform, and using the autoset function. All examples in the tutorial begin by resetting the digitizing oscilloscope to ...

Example 1: Displaying a Waveform Getting Started 1Ć8 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...

Example 1: Displaying a Waveform TDS 620A, 640A, & 644A User Manual 1Ć9 Figure 1-7 shows the display that results from the instrument reset. There areseveral 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 ...

Example 1: Displaying a Waveform Getting Started 1Ć10 The display shows the probe compensation signal. It is a 1 kHz square waveof approximately 0.5 V amplitude. You can adjust the size and placement ofthe waveform using the front-panel knobs. Figure 1-8 shows the main VERTICAL and HORIZONTAL sectio...

Example 1: Displaying a Waveform Getting Started 1Ć12 Figure 1-11: The Display After Pressing Autoset NOTE If the corners on your displayed signal look rounded or pointed (seeFigure 1-12), then you may need to compensate your probe. TheProbe Compensation section on page 3-110 explains how to com- pe...

TDS 620A, 640A, & 644A User Manual 1Ć13 Example 2: Multiple Waveforms In this example you learn how to display and control more than one waveformat a time. The VERTICAL section of the front panel contains the channel selectionbuttons. These are CH 1, CH 2, CH 3, CH 4, and MORE (Figure 1-13); on ...

Example 2: Multiple Waveforms TDS 620A, 640A, & 644A User Manual 1Ć15 Side Menu Title Ch2 Reference Indicator Figure 1-14: The Vertical Main Menu and Coupling Side Menu Pressing a channel (CH) button sets the vertical controls to that channel. Italso adds the channel to the display if that wavef...

Example 2: Multiple Waveforms Getting Started 1Ć16 Side Menu Title Figure 1-15: The Menus After Changing Channels Pressing the WAVEFORM OFF button removes the waveform for the current-ly selected channel. If the waveform you want to remove is not already se-lected, select that channel using the chan...

TDS 620A, 640A, & 644A User Manual 1Ć17 Example 3: Automated Measurements In this example you learn how to use the automated measurement system toget numeric readouts of important waveform characteristics. To use the automated measurement system, you must have a stable displayof your signal. Als...

Example 3: Automated Measurements TDS 620A, 640A, & 644A User Manual 1Ć19 Press here to remove menus from screen. Figure 1-17: Four Simultaneous Measurement Readouts The Measure menu lets you remove measurements you no longer wantdisplayed. You can remove any one measurement, or you can remove t...

Example 3: Automated Measurements Getting Started 1Ć20 General Purpose Knob Setting and Readout Highlighted Menu Item with Boxed Readout Value General Purpose Knob Icon Figure 1-18: General Purpose Knob Indicators There are several important things to observe on the screen: H The knob icon appears a...

TDS 620A, 640A, & 644A User Manual 1Ć23 Example 4: Saving Setups This example shows you how to save all the settings of the digitizing oscillo-scope and how to recall the setup later to quickly re-establish the previouslysaved state. The oscilloscope provides several storage locations where youc...

Example 4: Saving Setups Getting Started 1Ć24 Figure 1-20: Save/Recall Setup Menu 7. Press one of the To Setup side menu buttons to store the current instru-ment settings into that setup location. Remember which setup locationyou selected for use later. There are more setup locations than can be lis...

TDS 620A, 640A, & 644A User Manual 2Ć1 Overview This section describes the basic concepts of operating the digitizing oscillo-scope. Understanding the basic concepts of your digitizing oscilloscope willhelp you use it much more effectively. The first part, At a Glance, quickly shows you how the ...

TDS 620A, 640A, & 644A User Manual 2Ć3 At a Glance The At a Glance section contains illustrations of the display, the front and rear panels, and the menu system. These will help you understand and operatethe digitizing oscilloscope. This section also contains a visual guide to usingthe menu syst...

At a Glance TDS 620A, 640A, & 644A User Manual 2Ć5 Security Bracket GPIB Connector page 3-126 Centronics Connector (Optional on TDS 620A & TDS 640A) Principal Power Switch, page 1-3 Serial Number RS-232 Connector (Optional on TDS 620A & TDS 640A) Fuse, page 1-3 Power Connector, page 1-3 ...

At a Glance Operating Basics 2Ć6 The value entered with the general purpose knob Channel level and waveform source The acquisition status, page 3-3 The main menu with choices of major actions The side menuwith choices ofspecific actions Vertical scale, page 3-147 Horizontal scaleand time basetype, p...

At a Glance TDS 620A, 640A, & 644A User Manual 2Ć7 1. Press front-panel menu button. (Press SHIFT first if button label is blue.) 2. Press one of these buttons to select from main menu. 3. Press one of these buttons to select from side menu (if displayed). 4. If side menu item has an ad- justabl...

At a Glance TDS 520A, 524A, 540A, & 544A User Manual 2Ć9 Acquire Menu (see page 3-3) Press these but-tons: Cursor Menu (see page 3-17) Delayed Trigger Menu (see page 3-22) Display Menu – Color (TDS 524A & TDS 544A) (see page 3-12 ) To bring up these menus: Application Menu (see the Programme...

At a Glance TDS 620A, 640A, & 644A User Manual 2Ć11 Press these buttons: To bring up these menus: Utility Menu – I/O – GPIB (see page 3-126) Vertical Channel Menu( see page 3-147) Zoom Menu ( see page 3-162) Utility Menu – Calibration( see page ) Utility Menu – Diagnostics( see the Service manua...

TDS 620A, 640A, & 644A User Manual 2Ć13 Triggering This section describes the edge trigger of the main trigger system and ex-plores, in a general sense, the topic of triggering. This oscilloscope also haslogic and pulse triggers in the main trigger system and a delayed triggersystem. They are de...

Triggering Operating Basics 2Ć14 H AC Line Voltage — this trigger source is useful when you are looking atsignals related to the power line frequency. Examples include devicessuch as lighting equipment and power supplies. Because the digitizingoscilloscope generates the trigger, you do not have to i...

Triggering TDS 620A, 640A, & 644A User Manual 2Ć15 H Automatic — this trigger mode (auto mode) lets the oscilloscope acquirea waveform even if a trigger does not occur. Auto mode uses a timer thatstarts after a trigger event occurs. If another trigger event is not detectedbefore the timer times ...

Triggering Operating Basics 2Ć16 Holdoff Holdoff Trigger Points Trigger Level Holdoff Acquisition Interval Acquisition Interval Triggers are Not Recognized During Holdoff Time Figure 2-2: Trigger Holdoff Time Ensures Valid Triggering Holdoff is settable from 0% (minimum holdoff available) to 100% (m...

Triggering TDS 620A, 640A, & 644A User Manual 2Ć17 The adjustable trigger position defines where on the waveform record the trigger occurs. It lets you properly align and measure data within records. Thepart of the record that occurs before the trigger is the pretrigger portion. The part that oc...

Triggering Operating Basics 2Ć18 As mentioned earlier in this section there is also a delayed trigger system thatprovides an edge trigger (no pulse or logic triggers). When using the delayedtime base, you can also delay the acquisition of a waveform for a user-speci-fied time or a user-specified num...

TDS 620A, 640A, & 644A User Manual 2Ć19 Acquisition Acquisition is the process of sampling the analog input signal, converting itinto digital data, and assembling it into a waveform record. The oscilloscopecreates a digital representation of the input signal by sampling the voltagelevel of the s...

Acquisition Operating Basics 2Ć20 The digitizer can use the extra samples to perform additional processing,such as averaging or looking for minimum and maximum values. The digitizing oscilloscope creates a waveform record containing a user-spe-cified number of data points. Each record point represen...

Acquisition TDS 620A, 640A, & 644A User Manual 2Ć21 If you focus on only one channel at the maximum possible real-time rate, theTDS 524A and TDS 620A oscilloscopes can acquire at 500 Megasamples/second using both its digitizers, while the TDS 644A and TDS 640A oscillo-scopes can combine all four...

Acquisition TDS 620A, 640A, & 644A User Manual 2Ć23 Table 2-1: Sampling Mode Selection — 100 ns/Div to 50 ns/Div (When Fit to Screen is Off) Instrument andNumber of Channels 100 ns/Div 50 ns/Div TDS 544A & 540A,any 1 channel Real-time Real-time TDS 544A & 540A,any 2 channels Real-time Eq...

TDS 620A, 640A, & 644A User Manual 2Ć25 Scaling and Positioning Waveforms Scaling and positioning waveforms means increasing or decreasing theirdisplayed size and moving them up, down, right, and left on the display. Two display icons, the channel reference indicator and the record view, helpyou...

Scaling and Positioning Waveforms Operating Basics 2Ć26 You can adjust the vertical position of the selected waveform by moving it upor down on the display. For example, when trying to compare multiple wave-forms, you can put one above another and compare them, or you can overlaythe two waveforms on...

Scaling and Positioning Waveforms TDS 620A, 640A, & 644A User Manual 2Ć27 Aliasing When aliasing happens, you see a waveform with a frequency lower than the actual waveform being input or a waveform is not stable even though the lightnext to TRIG’D is lit. Aliasing occurs because the oscilloscop...

Scaling and Positioning Waveforms Operating Basics 2Ć28 FastFrame TM You can define and enable FastFrame TM (also called “segmented memory”) on the TDS 600A. This feature lets you capture multiple acquisitions in theacquisition memory of a single channel. Figure 2-10 shows how FastFramecombines the ...

Operating Basics 2Ć30 Measurements The digitizing oscilloscope not only displays graphs of voltage versus time, italso can help you measure the displayed information (see Figure 2-11). Ch 1 Period 10 ns Automated Measurements Graticule Ch 1 Frequency 100 MHz Cursors Cursor Readouts Figure 2-11: Grat...

Measurements TDS 620A, 640A, & 644A User Manual 2Ć31 The snapshot selection in the Measurement menu lets you display almost allof the measurements at once. You can read about snapshot under Snapshot of Measurements, on page 3-95. Automated measurements use readouts to show measurement status. Th...

Measurements Operating Basics 2Ć32 H Tracking mode cursors operate in tandem: you move both cursors at thesame time using the general purpose knob. To adjust the solid cursorrelative to the dashed cursor, you push the SELECT button to suspendcursor tracking and use the general purpose knob to make t...

TDS 620A, 640A, & 644A User Manual 3Ć3 Acquisition Modes The acquisition system has several options for converting analog data intodigital form. The Acquisition menu lets you determine the acquisition mode,whether or not to permit equivalent time sampling, and how to start and stopacquisitions. ...

Acquisition Modes Reference 3Ć4 Waveform Drawn on CRT Samples Acquired in Four Acquisition Intervals Displayed Record Points Acquisition Mode Use for fastest acquisition rate. This is the default mode. Use to reveal aliasing and for glitch detection. Provides the benefits of enveloping with the spee...

Acquisition Modes TDS 620A, 640A, & 644A User Manual 3Ć5 Hi Res Mode In Hi Res mode, the digitizing oscilloscope averages all samples taken duringan acquisition interval to create a record point. That average results in ahigher-resolution, lower-bandwidth waveform. This mode only works with real...

Acquisition Modes Reference 3Ć6 After each trigger event, the oscilloscope acquires data and then comparesthe min/max values from the current acquisition with those stored from pre-vious acquisitions. The final display shows the most extreme values for all theacquisitions for each point in the wavef...

Acquisition Modes TDS 620A, 640A, & 644A User Manual 3Ć7 To bring up the acquisition menu (Figure 3-2) press SHIFT ACQUIRE MENU. Acquisition Mode To choose how the digitizing oscilloscope will create points in the waveformrecord: Press SHIFT ACQUIRE MENU ➞ Mode (main) ➞ Sample, Peak Detect, Hi R...

Reference 3Ć10 Autoset The autoset function lets you quickly obtain and display a stable waveform ofusable size. Autoset automatically sets up the front panel controls based onthe characteristics of the input signal. It is much faster and easier than amanual control-by-control setup. Autoset makes a...

Autoset TDS 620A, 640A, & 644A User Manual 3Ć11 Table 3-2: Autoset Defaults Control Changed by Autoset to Selected channel Numerically lowest of the displayedchannels Acquire Mode Sample Acquire Repetitive Signal On Acquire Stop After RUN/STOP button only Display Style Vectors Display Intensity ...

Reference 3Ć12 Color (TDS 524A & TDS 644A) The TDS 524A & TDS 644A can display information in different colors. TheColor menu lets you choose palettes of colors and decide what colors toassign to what pieces of information. To bring up the Color menu: 1. Press DISPLAY to show the Display men...

Color TDS 620A, 640A, & 644A User Manual 3Ć13 Choose Palette You can choose a palette of 13 colors from a menu of pre-set palettes. 1. Choose the starting palette by selecting Palette from the main menu. 2. Select one of the available palettes in the side menu. Choose from Nor-mal, Bold, Hardcop...

Color Reference 3Ć14 ScrTxt Figure 3-5: Display Menu — Palette Colors 2. Select one of the 13 colors by pressing (repeatedly) Color in the sidemenu. 3. If you want to use the factory default for this color, press the side menuReset to Factory Color. 4. Choose Hue from the side menu and use the gener...

Color TDS 620A, 640A, & 644A User Manual 3Ć15 3. If you want to assign the selected math waveform to a specific color,press Color and cycle through the choices. 4. If you want the selected math waveform to be the same color as thewaveform it is based on, select Color Matches Contents. If the mat...

Color Reference 3Ć16 Select Options To define what color to show where a waveform crosses another waveform: 1. Press the Options main menu item. 2. Select that you wish to use a special color to mark collision zones bytoggling Collision Contrast in the side menu to ON. Restore Colors To restore colo...

TDS 620A, 640A, & 644A User Manual 3Ć17 Cursor Measurements Use the cursors to measure the difference (either in time or voltage) betweentwo locations in a waveform record. Cursors are made up of two markers that you position with the general pur-pose knob. You move one cursor independently or b...

Cursor Measurements Reference 3Ć18 NOTE When cursors measure certain math waveforms, the measurementmay not be of time, frequency, or voltage. Cursor measurement ofthose math waveforms that are not of time, frequency, or voltage isdescribed in Waveform Math, which begins on page 3-159. There are two...

Cursor Measurements TDS 620A, 640A, & 644A User Manual 3Ć19 In FastFrame mode, the @ shows the time position of the selected cursorrelative to the trigger point of the frame that the selected cursor is in. The D shows the time difference between the two cursors only if both cursors are in the sa...

Cursor Measurements Reference 3Ć20 Non-selected Cursor (Dashed Vertical Bar) Cursor Readout (Paired) Selected Cursor (Solid Vertical Bar) Position of Vertical Bar Cursors (Useful for Locating Cursors Outside the Display) Figure 3-11: Paired Cursor Menu and Readouts Mode Select the cursor mode you wa...

Cursor Measurements TDS 620A, 640A, & 644A User Manual 3Ć21 Time Units You can choose to display vertical bar cursor results in units of time or fre-quency. If you have Option 5 Video, you can also display the results in termsof video line number. Press CURSOR ➞ Time Units (main) ➞ seconds or 1/...

Reference 3Ć22 Delayed Triggering The TDS 600A Series oscilloscopes provide a main time base and a delayedtime base. The delayed time base, like the main time base, requires a triggersignal and an input source dedicated to that signal. You can only use delaywith respect to the main edge trigger and ...

Delayed Triggering TDS 620A, 640A, & 644A User Manual 3Ć23 H After Time waits the user-specified time, then waits for the next delayedtrigger event, and then acquires. H After Events waits for the specified number of delayed trigger events andthen acquires. H After Events/Time waits for the spec...

Delayed Triggering Reference 3Ć24 Time Delay (From Delay Trig Menu) Time Delay (From Delay Trig Menu) Start Posttrigger Acquisition (Trigger on nth Delayed Trigger Event) Time Delay (From Horiz Menu) Time Delay (From Delay Trig Menu) Waiting for nth Event (Where n=5) Main Trigger Point Start Posttri...

Delayed Triggering Reference 3Ć26 The Source menu lets you select which input will be the delayed triggersource. 7. Press Source (main) ➞ Ch1, Ch2, Ch3 (Ax1 on the TDS 524A & TDS 620A), Ch4 (Ax2 on the TDS 524A & TDS 620A), or Auxiliary (not available on the TDS 524A & TDS 620A) (side). ...

Reference 3Ć28 Display Modes The digitizing oscilloscope can display waveform records in different ways.The Display menu lets you adjust the oscilloscope display style, intensitylevel, graticule, and format. To bring up the Display menu: 1. Press DISPLAY to show the Display menu. 2. On the TDS 644A ...

Display Modes TDS 620A, 640A, & 644A User Manual 3Ć29 H Vectors has the display draw vectors (lines) between the record points. H Dots display waveform record points as dots. H Intensified Samples also displays waveform record points as dots.However, the points actually sampled are displayed in ...

Display Modes Reference 3Ć30 Display Readout Readout options control whether the trigger indicator, trigger level bar, andcurrent date and time appear on the display. The options also control whatstyle trigger level bar, long or short, is displayed. 1. Press DISPLAY ➞ Readout (main). 2. Toggle Displ...

Display Modes TDS 620A, 640A, & 644A User Manual 3Ć31 Filter Type The display filter types are sin(x)/x interpolation and linear interpolation. Formore information see the Concepts section, page 2-21. Press DISPLAY ➞ Filter (main) ➞ Sin(x)/x Interpolation or Linear Interpo- lation (side). NOTE W...

Reference 3Ć34 Edge Triggering An edge trigger event occurs when the trigger source passes through a specified voltage level in a specified direction (the trigger slope). You will likelyuse edge triggering for most of your measurements. You can select the edge source, coupling, slope, level, and mod...

Edge Triggering TDS 620A, 640A, & 644A User Manual 3Ć35 Figure 3-19: Main Trigger Menu — Edge Type Coupling To select the coupling you want: Press TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞ Cou- pling (main) ➞ DC, AC, HF Rej, LF Rej, or Noise Rej (side). H DC passes all of the input signal. In...

Edge Triggering Reference 3Ć36 Slope To select the slope that the edge trigger will occur on: 1. Press the TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞ Slope (main). 2. Alternatives for slope are the rising and falling edges. Level Press the TRIGGER MENU ➞ Type (main) ➞ Edge (pop-up) ➞ Level (main) ...

Reference 3Ć38 Fast Fourier Transforms Advanced DSP Math (optional on TDS 620A & TDS 640A), provides the Fast Fourier Transform (FFT). The FFT allows you to transform a waveform from adisplay of its amplitude against time to one that plots the amplitudes of thevarious discrete frequencies the wa...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć39 zontal scale for FFT math waveforms is always expressed in frequency perdivision with the beginning (left-most point) of the waveform representing zerofrequency (DC). The FFT waveform is based on digital signal processing (DSP) of d...

Fast Fourier Transforms Reference 3Ć40 Figure 3-21: Define FFT Waveform Menu 5. If the selected math waveform is not FFT, press Change Math Definition (side) ➞ FFT (main). See Figure 3-21. 6. Press Set FFT Source to (side) repeatedly until the channel sourceselected in step 1 appears in the menu lab...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć41 H Hamming — Very good window for resolving frequencies that arevery close to the same value with somewhat improved amplitudeaccuracy over the rectangular window. H Hanning — Very good window for measuring amplitude accuracybut degra...

Fast Fourier Transforms Reference 3Ć42 Cursor Measurements of an FFT Once you have displayed an FFT math waveform, use cursors to measure itsfrequency amplitude or phase angle. 1. Be sure MORE is selected in the channel selection buttons and that theFFT math waveform is selected in the More main men...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć43 Figure 3-23: Cursor Measurement of an FFT Waveform 10. Press Function (main) ➞ Paired (side). 11. Use the technique just outlined to place the vertical bar of each paired cursor to the points along the horizontal axis you are intere...

Fast Fourier Transforms Reference 3Ć44 The FFT Frequency Domain Record The following topics discuss the relation of the source waveform to the recordlength, frequency resolution, and frequency range of the FFT frequencydomain record. (The FFT frequency domain waveform is the FFT mathwaveform that yo...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć45 Zero Phase Reference Waveform Record > 10 K Waveform Record ≤ 10 K FFT Time Domain Record = Waveform Record Zero Phase Reference FFT Time Domain Record = 10k Figure 3-24: Waveform Record vs. FFT Time Domain Record FFTs Transform ...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć47 Record Length Most often, you will want to use a short record length because more of theFFT waveform can be seen on screen and long record lengths can slowoscilloscope response. However, long record lengths lower the noise relativet...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć49 Nyquist Frequency Point Frequency Amplitude Aliased Frequencies Actual Frequencies Figure 3-26: How Aliased Frequencies Appear in an FFT Considerations for Phase Displays When you set up an FFT math waveform to display the phase ang...

Fast Fourier Transforms Reference 3Ć50 H For records with a 15 K length, set the trigger position to 33%. Use thehorizontal position knob to move the trigger T on screen to the centerhorizontal graticule line. H For records with 30 K, 50 K, or 60 K lengths (not all lengths are availablefor all TDS m...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć51 Windowing Process — The oscilloscope multiplies the FFT time domain record by one of four FFT windows before it inputs the record to the FFTfunction. Figure 3-27 shows how the time domain record is processed. The FFT windowing acts ...

Fast Fourier Transforms Reference 3Ć52 FFT Time Domain Record FFT Time Domain Record After Windowing FFT Window FFT Frequency Domain Record FFT Xs Figure 3-27: Windowing the FFT Time Domain Record You can often determine the best window empirically by first using the windowwith the most frequency re...

Fast Fourier Transforms TDS 620A, 640A, & 644A User Manual 3Ć53 Window Characteristics — When evaluating a window for use, you may want to examine how it modifies the FFT time domain data. Figure 3-28shows each window, its bandpass characteristic, bandwidth, and highest sidelobe. Consider the fo...

Fast Fourier Transforms Reference 3Ć54 Rectangular Window 0 dB -20 -40 -50 Hanning Window 0 dB -20 -40 -60 -80 Hamming Window 0 dB -20 -40 -60 Blackman-Harris Window 0 dB -20-40-60-80 -100 -101 FFT Window Type Bandpass Filter 0.89 -3 dB Bandwidth Highest Side Lobe 1.28 1.28 1.28 -13 dB –32 dB –43 dB...

File System Reference 3Ć56 NOTE The amount of free space on the disk is shown in the upper rightcorner of the display. The digitizing oscilloscope shows the amountin K bytes. To convert the amount to bytes, you simply multiply theK bytes amount times 1024. Thus, the 711 kB shown in Figure 3-29= 711 ...

File System TDS 620A, 640A, & 644A User Manual 3Ć57 Figure 3-30: File System — Labelling Menu Copy To copy a file or directory, turn the general purpose knob until it scrolls thecursor over the name of the file to copy. Then, press the side menu Copybutton. The file menu will reappear with the n...

File System Reference 3Ć58 The labelling menu should appear. Turn the general purpose knob or use themain-menu arrow keys to select each letter. Press Enter Char from the mainmenu to enter each letter. When you have entered the name, press the sidemenu OK Accept item. (See Figure 3-30) Confirm Delet...

TDS 520A, 524A, 540A, & 544A User Manual 3Ć59 Hardcopy You can get a copy of the digitizing oscilloscope display by using the hardco-py feature. Depending on the output format you select, you create either animage or a plot. Images are direct bit map representations of the digitizingoscilloscope...

Hardcopy Reference 3Ć60 Before you make a hardcopy, you need to set up communications and hard-copy parameters. This discussion assumes that the hardcopy device isalready connected to the GPIB port on the rear panel. If that is not the casesee Connection Strategies on page 3-63. Setting Communicatio...

Hardcopy TDS 520A, 524A, 540A, & 544A User Manual 3Ć61 Setting Hardcopy Parameters To specify the hardcopy format, layout, and type of port using the hardcopymenu: 1. Press SHIFT HARDCOPY MENU to bring up the Hardcopy menu. 2. Press Format (main) ➞ Thinkjet, Deskjet, Laserjet, Epson, DPU-411, DP...

Hardcopy Reference 3Ć62 To stop and discard the hardcopy being sent, press HARDCOPY again while the hardcopy in process message is still on screen. To add additional hardcopies to the printer spool, press HARDCOPY againafter the hardcopy in process message is removed from the screen. You can add har...

Hardcopy TDS 520A, 524A, 540A, & 544A User Manual 3Ć63 Date and Time Display Figure 3-33: Date and Time Display 5. Use the general purpose knob or the keypad to set the parameter youhave chosen to the value desired. (The format when using the keypad isday.month. For example, use 23.6 for the 23 ...

Hardcopy Reference 3Ć64 Strategies for actually printing a copy include: H Send output straight to a printer/plotter. H Send the data to a computer to print from there and/or to import into yourfavorite desktop publishing or other application package. H Send your data to a floppy disk file (optional...

Hardcopy TDS 520A, 524A, 540A, & 544A User Manual 3Ć65 GPIB Cable Digitizing Oscilloscope PC Compatible Centronics orRS-232 Cable Hardcopy Device Figure 3-35: Connecting the Digitizing Oscilloscope and Hardcopy Device Via a PC If your controller is PC-compatible and it uses the Tektronix GURU or...

Hardcopy Reference 3Ć66 5. Type: IBRDF <Filename>where <Filename> is a valid DOS file nameyou want to call your hardcopy information. It should be v 8 characters long with up to a 3 character extension. For example, you could type“ibrdf screen1”. 6. Exit the IBIC program by typing: EXIT ...

TDS 620A, 640A, & 644A User Manual 3Ć67 Help The on-line help system provides brief information about each of the digitizingoscilloscope controls. To use the on-line help system: Press HELP to provide on-screen information on any front panel button, knobor menu item (see Figure 3-36). When you p...

Reference 3Ć68 Horizontal Control You can control the horizontal part of the display (the time base) using thehorizontal menu and knobs. By changing the horizontal scale, you can focus on a particular portion of awaveform. By adjusting the horizontal position, you can move the waveformright or left ...

Horizontal Control TDS 620A, 640A, & 644A User Manual 3Ć69 At the top of the display, the Record View shows the size and location of the waveform record and the location of the trigger relative to the display (seeFigure 3-38). The Time Base readout at the lower right of the display shows the tim...

Horizontal Control Reference 3Ć70 You also can select Delayed Runs After Main or Delayed Triggerable. Formore information on how to use these two menu items, see Delayed Trigger- ing on page 3-22. Trigger Position To define how much of the record will be pretrigger and how much posttriggerinformatio...

Horizontal Control Reference 3Ć72 Figure 3-39: Horizontal Menu — FastFrame Setup FastFrame Interactions — Envelope, Average, and HiRes form the envelope or average following the last frame of the concatenated record. Forexample, if average or HiRes acquisition modes are selected and the framecount i...

TDS 620A, 640A, & 644A User Manual 3Ć73 Limit Testing Limit testing provides a way to automatically compare each incoming or mathwaveform against a template waveform. You set an envelope of limits arounda waveform and let the digitizing oscilloscope find waveforms that fall outsidethose limits (...

Limit Testing Reference 3Ć74 NOTE The template will be smoother if you acquire the template waveformusing Average acquisition mode. If you are unsure how to do this,see Acquisition Modes on page 3-7. Once you have selected a source, select a destination for the template. 2. Press Template Destinatio...

Limit Testing TDS 620A, 640A, & 644A User Manual 3Ć75 If you wish to create another limit test template, store it in another des-tination to avoid overwriting the template you have just created. If you wish to view the template you have created, press the MOREbutton. Then press the button corres...

Limit Testing Reference 3Ć76 H If you want to send a hardcopy command when waveform data exceeds the limits set, toggle Hardcopy if Condition Met (side) toON. You can set the hardcopy system to send the hardcopy to the filesystem (optional on the TDS 620A & TDS 640A). (Do not forget toset up the...

Limit Testing TDS 620A, 640A, & 644A User Manual 3Ć77 Multiple Waveform Comparisons When comparing one or more waveforms, each against a common templateor against its own template, consider the following operating characteristics: H You should set Horizontal Lock to None in the Zoom side menu (p...

Reference 3Ć78 Logic Triggering There are two classes of logic triggering: pattern and state. A pattern trigger occurs when the logic inputs to the logic function you select cause the function to become TRUE (or at your option FALSE). When youuse a pattern trigger, you define: H The precondition for...

Logic Triggering TDS 620A, 640A, & 644A User Manual 3Ć79 At the bottom of the display, the Trigger readout shows some of the keyparameters of the logic trigger (see Figure 3-42). Trigger Class = State Ch 1, 2, 3 Inputs = High, Don’t Care, High Ch 4 Input =Rising Edge Logic = OR Figure 3-42: Logi...

Logic Triggering TDS 620A, 640A, & 644A User Manual 3Ć81 Figure 3-43: Logic Trigger Menu Trigger When This menu item lets you determine if the oscilloscope will trigger when thelogic condition is met (Goes TRUE) or when the logic condition is not met(Goes FALSE). (The True when less than and Tru...

Logic Triggering Reference 3Ć82 Mode & Holdoff You can change the holdoff time and select the trigger mode using this menuitem. 1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞ Class (main) ➞ Pattern or State (pop-up) ➞ Mode & Holdoff (main) ➞ Auto or Normal (side). H In Auto mode the ...

Logic Triggering TDS 620A, 640A, & 644A User Manual 3Ć83 Define a Time Qualified Pattern Trigger You can also time qualify a pattern logic trigger. That is, you specify a timethat the boolean logic function (AND, NAND, OR, or NOR) must be TRUE(logic high). You also choose the type of time qualif...

Logic Triggering Reference 3Ć84 Logic Function (AND) Becomes TRUE Logic Function Becomes FALSE and Triggers Acquisition Time Logic Function is TRUE Time Logic Function Must be TRUE Figure 3-44: Logic Trigger Menu — Time Qualified TRUE When you select State logic triggering, the oscilloscope uses cha...

Reference 3Ć86 Measurement System There are various ways to measure properties of waveforms. You can usegraticule, cursor, or automatic measurements. This section describes auto- matic measurements; cursors and graticules are described elsewhere. (SeeCursor Measurements on page 3-17 and Measurements...

Measurement System TDS 620A, 640A, & 644A User Manual 3Ć89 The readout area for measurements is on the right side of the waveformwindow. You can display and continuously update as many as four measure-ments at any one time. When menus are displayed, the readouts appear inthe graticule area. If t...

Measurement System Reference 3Ć90 H To vary the source for measurements, simply select the other channeland then choose the measurements you want. H Be careful when taking automatic measurements on noisy signals.You might measure the frequency of the noise and not the desiredwaveform. Your digitizin...

Measurement System TDS 620A, 640A, & 644A User Manual 3Ć91 Gated Measurements The gating feature lets you limit measurements to a specified portion of thewaveform. When gating is Off, the oscilloscope makes measurements overthe entire waveform record. When gating is activated, vertical cursors a...

Measurement System Reference 3Ć92 NOTE Cursors are displayed relative to the selected waveform. If you aremaking a measurement using two waveforms, this can be a sourceof confusion. If you turn off horizontal locking and adjust the hori-zontal position of one waveform independent of the other, thecu...

Measurement System TDS 620A, 640A, & 644A User Manual 3Ć93 2. Press High Ref , Mid Ref , Low Ref , or Mid2 Ref (side). H High Ref — Sets the high reference level. The default is 90%. H Mid Ref — Sets the middle reference level. The default is 50%. H Low Ref — Sets the low reference level. The de...

Measurement System Reference 3Ć94 2. Press Measure Delay to (side) repeatedly to choose the delay to wave- form. The choices are Ch1, Ch2, Ch3, Ch4 (on the TDS 644A &TDS 640A); Ch1, Ch2, Ax1, Ax2 (on the TDS 524A & TDS 620A); andMath1, Math2, Math3, Ref1, Ref2, Ref3, and Ref4. Figure 3-49: M...

Measurement System TDS 620A, 640A, & 644A User Manual 3Ć95 Creating the Delay Measurement — Once you have specified the waveforms you are measuring between and which edges to use, you need tonotify the digitizing oscilloscope to proceed with the measurement. Press Delay To (main) ➞ OK Create Mea...

Measurement System Reference 3Ć96 To use snapshot, obtain a stable display of the waveform to be measured.Pressing AUTOSET may help. 1. Press MEASURE ➞ SNAPSHOT (main). 2. Press either SNAPSHOT (main) or AGAIN (side) to take another snap-shot. NOTE The snapshot display tells you the channel that the...

TDS 520A, 524A, 540A, & 544A User Manual 3Ć97 Probe Accessories The probe you use and how you connect it to a signal source affect theoscilloscope acquisition of the waveform record. Two important factors areground lead inductance (introduced by the probe) and the physical layout ofyour circuit ...

Probe Accessories Reference 3Ć98 4 Inch Ground Lead Low-Inductance Ground Lead Figure 3-52: Signal Variation Introduced by Probe Ground Lead (1 ns/division) The following descriptions explain how to use many of the accessories thatcame with your probe. Figure 3-53 shows both standard and optional pr...

Probe Accessories Reference 3Ć100 Marker Rings The marker rings help you keep track of individual probes and signal sourceswhen you have a complicated test setup. Use the marker rings whenever youwant to identify a particular probe. Long Ground Leads Use long ground leads when a long reach is import...

Probe Accessories TDS 520A, 524A, 540A, & 544A User Manual 3Ć101 Probe-Tip-to-Circuit Board Adapters The probe-tip-to-circuit board adapters let you design minimum inductancetest points into your next circuit board. That adapter provides maximumperformance for the probe, because it virtually eli...

Probe Accessories Reference 3Ć102 Probe-Tip-to-Chassis Adapter The probe-tip-to-chassis adapter makes your test point accessible withoutremoving instrument covers or panels. It provides an easy-access, low-induc-tance test point anywhere on your circuit. The probe-tip-to-chassis adapterhas the same ...

Reference 3Ć104 Probe Cal This oscilloscope lets you compensate the entire signal path, from probe tip todigitized signal, to improve the gain and offset accuracy of the probe. Byexecuting Probe Cal on a channel with its probe installed, you can optimize the oscilloscope capability to make accurate ...

Probe Cal Reference 3Ć106 Figure 3-55: Probe Cal Menu and Gain Compensation Display 11. If the Probe Offset Compensation message is displayed, continue with step 15; otherwise, continue with step 12. 12. If the Compensation Error message is displayed, continue with step 13; otherwise continue with s...

Probe Cal TDS 620A, 640A, & 644A User Manual 3Ć107 19. If desired, repeat this procedure beginning at step 1 to compensate for other probe/channel combinations. But before you do so, be sure youtake note of the following requirements: H Remember to first low frequency compensate any passive prob...

Reference 3Ć110 Probe Compensation Passive probes require compensation to ensure maximum distortion-freeinput to the digitizing oscilloscope and to avoid high frequency amplitudeerrors (see Figure 3-57). Probe Compensated Correctly Probe Overcompensated Probe Undercompensated Figure 3-57: How Probe ...

Reference 3Ć112 Probe Selection The probes included with your digitizing oscilloscope are useful for a widevariety of tasks. However, for special measurement situations you sometimesneed different probes. This section helps you select the right probe for thejob. Once you have decided the type of pro...

Probe Selection TDS 620A, 640A, & 644A User Manual 3Ć113 Low Impedance (Z O ) Probes Low impedance probes measure frequency more accurately than generalpurpose probes, but they make less accurate amplitude measurements. Theyoffer a higher bandwidth to cost ratio. These probes must be terminated ...

Probe Selection Reference 3Ć114 Active voltage probes, sometimes called “FET” probes, use active circuitelements such as transistors. There are three classes of active probes: H High speed active H Differential active H Fixtured active Active voltage measuring probes use active circuit elements in t...

Probe Selection TDS 620A, 640A, & 644A User Manual 3Ć115 amplifiers) to precisely connect your instrument to your device-under-test.These probes have the same electrical characteristics as high speed, activeprobes but use a smaller mechanical design. Current probes enable you to directly observe...

Probe Selection Reference 3Ć116 Optical probes let you blend the functions of an optical power meter with thehigh-speed analog waveform analysis capability of an oscilloscope. You havethe capability of acquiring, displaying, and analyzing optical and electricalsignals simultaneously. Applications in...

Probe Selection TDS 620A, 640A, & 644A User Manual 3Ć117 Table 3-7 lists TDS 600A compatible probes classified by type. Table 3-7: TDS 600A Compatible Probes Probe Type Tektronix Model Description Passive, high impedancevoltage P6139A (std.)P6101A 10X, 500 MHz1X, 15 MHz Passive, SMD P6563AS 20X,...

TDS 620A, 640A, & 644A User Manual 3Ć119 Pulse Triggering Pulse triggering can be very useful. For example, you might be testing aproduct with a glitch in the power supply. The glitch appears once a day. Soinstead of sitting by and waiting for it to appear, you can use pulse triggeringto automat...

Pulse Triggering Reference 3Ć122 H In Normal mode the oscilloscope acquires a waveform only if there isa valid trigger. (You can force a single acquisition by pressing FORCETRIGGER.) 2. To change the holdoff time, press Holdoff (side). Use the general pur-pose knob or the keypad to enter the value i...

Pulse Triggering TDS 620A, 640A, & 644A User Manual 3Ć123 H If you select Set to 50%, you cause the digitizing oscilloscope to searchfor the point halfway between the peaks of the trigger source signal andset the trigger level to that point. When you select the pulse class Runt, the oscilloscope...

Pulse Triggering Reference 3Ć124 Selected Trigger Bar at Upper Threshold Runt Pulse Crosses First Threshold Only, Recrosses First Threshold Level, and Triggers Acquisition Unselected Trigger Bar at Lower Threshold Figure 3-63: Main Trigger Menu—Runt Class Thresholds To set the two threshold levels u...

Pulse Triggering TDS 620A, 640A, & 644A User Manual 3Ć125 H Regardless of the polarity setting, triggering occurs at the point the runtpulse recrosses its first threshold. When you select the pulse class Width, the oscilloscope will trigger on apulse narrower (or wider) than some specified range...

Reference 3Ć126 Remote Communication You may want to integrate your oscilloscope into a system environment andremotely control your oscilloscope or exchange measurement or waveformdata with a computer. You can control your oscilloscope remotely via theIEEE Std 488.2–1987 (GPIB) interface. GPIB enabl...

Remote Communication TDS 620A, 640A, & 644A User Manual 3Ć127 GPIB Device GPIB Device GPIB Device GPIB Device GPIB Device GPIB Device GPIB Device Figure 3-64: Typical GPIB Network Configuration Cables — An IEEE Std 488.1–1987 GPIB cable (available from Tektronix, part number 012–0991–00) is requ...

Remote Communication Reference 3Ć128 To set up remote communications, ensure that your oscilloscope is physicallycabled to the controller and that the oscilloscope parameters are correctly set.Plug an IEEE Std 488.2–1987 GPIB cable into the GPIB connector on theoscilloscope rear panel and into the G...

Reference 3Ć130 Saving and Recalling Setups You may want to save and reuse setups for many reasons. For example, afterchanging the setting during the course of an experiment, you may want toquickly return to your original setup. You can save and recall up to ten instru-ment setups from internal osci...

Saving and Recalling Settings TDS 620A, 640A, & 644A User Manual 3Ć131 To store a setup to disk (optional on the TDS 620A & TDS 640A), press ToFile. Then use the general purpose knob to select the exact file from theresulting scrollbar list. Finally, press the side-menu Save To Selected File...

Saving and Recalling Setups Reference 3Ć132 H If the checksum calculation is unsuccessful, displays a warning message;if the checksum calculation is successful, displays a confirmation mes-sage. Running File Utilities To run file utilities (optional on the TDS 620A & TDS 640A), see the File Syst...

TDS 620A, 640A, & 644A User Manual 3Ć133 Saving and Recalling Waveforms You can store a waveform in any of the four internal reference memories ofthe digitizing oscilloscope. That information is retained even when you turnthe oscilloscope off or unplug it. You can save any combination of differe...

Saving and Recalling Waveforms Reference 3Ć134 Figure 3-69: Save Waveform Menu Deleting Waveforms You can choose the Delete Refs main menu item and then select the refer-ences you no longer need from the side menu (Delete Ref1, Delete Ref2,Delete Ref3, Delete Ref4, or Delete All Refs). Deleting All ...

Reference 3Ć136 Selecting Channels The selected channel is the channel that the digitizing oscilloscope applies all waveform-specific activities to (such as measurements or vertical scale andposition). The channel readout shows the selected channel in inverse video in the lowerleft corner of the dis...

Selecting Channels TDS 620A, 640A, & 644A User Manual 3Ć137 To selecting a channel: Pressing CH 1, CH 2, CH 3 (AUX 1 on the TDS 620A & TDS 524A), or CH 4(AUX 2 on the TDS 620A & TDS 524A) turns the channel on if it is not al-ready on. You do not use the channel selection buttons when tri...

Signal Path Compensation TDS 620A, 640A, & 644A User Manual 3Ć139 Figure 3-73: Performing a Signal Path Compensation

Reference 3Ć140 Status The Status menu lets you see information about the oscilloscope state. To operate the Status menu: Press SHIFT STATUS ➞ Status (main) ➞ System, Display, Trigger, Waveforms, or I/O (side). Note: some oscilloscopes do not have a main Status menu. On these instruments, press SHIF...

Status TDS 620A, 640A, & 644A User Manual 3Ć141 To display the banner (firmware version, options, copyright, and patents): NOTE Some TDS 644A oscilloscopes do not have a Status main menuwith a banner. However, all instruments display the banner briefly atpower-on. Press SHIFT STATUS ➞ Banner (ma...

Reference 3Ć142 Triggering Triggers determine when the digitizing oscilloscope starts acquiring anddisplaying a waveform. The TDS 600A has four types of trigger: edge, logic,pulse, and, with option 5, video. Although these triggers are unique, they have some common characteristicsthat can be defined...

Triggering TDS 620A, 640A, & 644A User Manual 3Ć143 To Set to 50% You can quickly obtain an edge or pulse trigger (except for the Runt class) bypressing SET LEVEL TO 50%. The oscilloscope sets the trigger level to thehalfway point between the peaks of the trigger signal. You can also set the lev...

Triggering Reference 3Ć144 H When READY is lighted, it means the digitizing oscilloscope can accept avalid trigger event, and the digitizing oscilloscope is waiting for that eventto occur. H When ARM is lighted, it means the trigger circuitry is filling the pretriggerportion of the waveform record. ...

Triggering TDS 620A, 640A, & 644A User Manual 3Ć145 The trigger point indicator shows position. It can be positioned horizontally offscreen, especially with long record length settings. The trigger level barshows only the trigger level. It remains on screen, regardless of the horizontalposition,...

TDS 620A, 640A, & 644A User Manual 3Ć147 Vertical Control You can control the vertical position and scale of the selected waveform usingthe vertical menu and knobs. By changing the vertical scale, you can focus on a particular portion of awaveform. By adjusting the vertical position, you can mov...

Vertical Control Reference 3Ć148 Vertical Readout Figure 3-79: Vertical Readouts and Channel Menu Coupling To choose the type of coupling for attaching the input signal to the verticalattenuator for the selected channel and to set its input impedance: Press VERTICAL MENU ➞ Coupling (main) ➞ DC, AC, ...

Vertical Control TDS 620A, 640A, & 644A User Manual 3Ć149 Bandwidth To eliminate the higher frequency components, change the bandwidth of theselected channel: Press VERTICAL MENU ➞ Bandwidth (main) ➞ Full, 100 MHz, or 20 MHz (side). Fine Scale Press VERTICAL MENU ➞ Fine Scale (main) to make fine...

Waveform Differentation TDS 620A, 640A, & 644A User Manual 3Ć151 Derivative Math Waveform Source Waveform Figure 3-80: Derivative Math Waveform 5. Press Set Function to (side). Repeatedly press the same button (or usethe general purpose knob) until diff appears in the menu label. 6. Press OK Cre...

Waveform Differentation Reference 3Ć152 Figure 3-81: Peak-Peak Amplitude Measurement of a Derivative Waveform Cursor Measurement of a Derivative Waveform You can also use cursors to measure derivative waveforms. Use the sameprocedure as is found under Waveform Integration on page 3-155. When using t...

Reference 3Ć154 Waveform Integration Advanced DSP Math (optional on TDS 620A & TDS 640A), provides wave- form integration that allows you to display an integral math waveform that isan integrated version of the acquired waveform. Such waveforms find use inthe following applications: H Measuring ...

Waveform Integration TDS 620A, 640A, & 644A User Manual 3Ć155 5. Press Set Function to (side). Repeatedly press the same button untilintg appears in the menu label. 6. Press OK Create Math Waveform (side) to turn on the integral mathwaveform. You should now have your integral math waveform on sc...

Waveform Integration Reference 3Ć156 6. Read the integrated voltage over time between the cursors in volt-seconds from the D : readout. Read the integrated voltage over time between the selected cursor and the reference indicator of the mathwaveform from the @: readout. See Figure 3-83. Source Wavef...

Waveform Integration TDS 620A, 640A, & 644A User Manual 3Ć157 H Read the integrated voltage over time between the X of the selected cursor and the reference indicator of the math waveform from the @:readout. H Read the time difference between the long vertical bars of the paired cursors from the...

TDS 620A, 640A, & 644A User Manual 3Ć159 Waveform Math You can mathematically manipulate your waveforms. For example, you mighthave a waveform clouded by background noise. You can obtain a cleanerwaveform by subtracting the background noise from your original waveform. This section describes the...

Waveform Math Reference 3Ć160 NOTE If your digitizing oscilloscope is equipped with Advanced DSP Math(optional on TDS 620A & TDS 640A), the menu item FFT will be atthe same brightness as the menu items Single Wfm Math andDual Wfm Math; otherwise, FFT will be dimmed. See pages 3-38, 3-150, and 3-...

Waveform Math TDS 620A, 640A, & 644A User Manual 3Ć161 Figure 3-85: Dual Waveform Math Main and Side Menus Dual Wfm Math 1. Select the sources with MORE ➞ Math1, Math2, or Math3 (main) ➞ Change Math waveform definition (side) ➞ Dual Wfm Math (main) ➞ Set 1st Source to and Set 2nd Source to (side...

Reference 3Ć162 Zoom At times, you may want to expand or compress a waveform on the displaywithout changing the acquisition parameters. You can do that with the zoomfeature. When you zoom in on a waveform on the display, you expand a portion of thewaveform. The digitizing oscilloscope may need to sh...

Zoom TDS 620A, 640A, & 644A User Manual 3Ć163 NOTE Although zoom must be turned on to control which waveforms zoomaffects, the setting for Horizontal Lock affects which waveformsthe horizontal control positions whether zoom is on or off. The rulesfor the three settings are listed in step 2. Only...

Zoom Reference 3Ć164 Reset Zoom To reset all zoom factors to their defaults (see Table 3-10), press ZOOM ➞ Reset Zoom Factors (side). Table 3-10: Zoom Defaults Parameter Setting Zoom Vertical Position 0 Zoom Vertical Gain 1X Zoom Horizontal Position Tracking Horizontal Position Zoom Horizontal Gain ...

TDS 520A, 524A, 540A, & 544A User Manual AĆ1 Appendix A: Options and Accessories This section describes the various options as well as the standard and option-al accessories that are available for the TDS 500A Digitizing Oscilloscopes. The following options are available: Options A1–A5: Internat...

Appendix A: Options and Accessories Appendices AĆ2 Warranty-Plus Service Options The following options add to the services available with the standard warranty.(The standard warranty appears following the title page in this manual.) H Option M2: When Option M2 is ordered, Tektronix provides five yea...

Appendix A: Options and Accessories Appendices AĆ4 constant, or a ratio calibration technique. The calibration is in compliance withUS MIL–STD–45662A. This option also includes a test data report for theinstrument. The following standard accessories are included with the digitizing oscillo-scope: Ta...

Appendix A: Options and Accessories TDS 520A, 524A, 540A, & 544A User Manual AĆ5 Table A-3: Probe Accessories (Cont.) Accessory Part Number Six-inch Alligator Clip Ground Lead 196–3305–00 Screwdriver: adjustment tool, metal tip 003–1433–00 SMT KlipChip TM 206–0364–00 Accessory Pouch 016–0708–00 ...

Appendix A: Options and Accessories Appendices AĆ8 Accessory Software The following optional accessories are Tektronix software products recom-mended for use with your digitizing oscilloscope: Table A-6: Accessory Software Software Part Number EZ-Test Program Generator S45F030 Wavewriter: AWG and wa...

TDS 620A, 640A, & 644A User Manual AĆ9 Appendix B: Algorithms TDS 600A Digitizing Oscilloscopes can take 25 automatic measurements. Byknowing how they make these calculations, you may better understand howto use your TDS 600A and how to interpret your results. TDS 600A Digitizing Oscilloscopes u...

Appendix B: Algorithms Appendices AĆ10 2. It splits the histogram into two sections at the halfway point between Min and Max (also called Mid ). 3. The level with the most points in the upper histogram is the High value, and the level with the most points in the lower histogram is the Low value. (Ch...

Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual AĆ11 End — is the location of the end of the measurement zone (X-value). It is ( – 1.0) samples unless you are making a gated measurement. When you use gated measurements, it is the location of the right verticalcursor. Hysteresis — The h...

Appendix B: Algorithms Appendices AĆ12 MidRef + (Hysteresis x Amplitude) MidRef – (Hysteresis x Amplitude) MidRef MCross1 (StartCycle) MCross2 MCross3 (EndCycle) Figure A-1: MCross Calculations Waveform[<0.0 ... RecordLength–1.0>] — holds the acquired data. TPOS — is the location of the sample...

Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual AĆ13 For details of the integration algorithm, see page A-19. Cycle Area Amplitude (voltage) measurement. The area over one waveform cycle. Fornon-cyclical data, you might prefer to use the Area measurement. If StartCycle = EndCycle then ...

Appendix B: Algorithms Appendices AĆ14 For details of the integration algorithm, see page A-19. Delay Timing measurement. The amount of time between the and crossings of two different traces, or two different places on the same trace. Delay measurements are actually a group of measurements. To get a...

Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual AĆ15 High HighRef LowRef Low TLF THF Fall Time Figure A-2: Fall Time Frequency Timing measurement. The reciprocal of the period. Measured in Hertz (Hz)where 1 Hz = 1 cycle per second. If Period = 0 or is otherwise bad, return an error. Fr...

Appendix B: Algorithms Appendices AĆ16 Maximum Amplitude (voltage) measurement. The maximum voltage. Typically the mostpositive peak voltage. Examine all # samples from !! to inclusive, and set % equal to the greatest magnitude # value found. Mean The arithmetic mean for one waveform. Remember that ...

Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual AĆ17 Negative Width Timing measurement. The distance (time) between (default = 50%) amplitude points of a negative pulse. If = ‘–’ then = – else = – Peak to Peak Amplitude measurement. The absolute difference between the maximum andminimu...

Appendix B: Algorithms Appendices AĆ18 If the target waveform leads the reference waveform, phase is positive; if itlags, negative. Phase is not available in the Snapshot display. Positive Duty Cycle Timing measurement. The ratio of the positive pulse width to the signal peri-od, expressed as a perc...

Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual AĆ19 3. From TLR , continue the search, looking for a crossing of HighRef . Update TLR if subsequent LowRef crossings are found. If a HighRef crossing is found, it becomes the high rise time or THR . (Use linear interpolation if necessary...

Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual AĆ21 If some samples in the waveform are missing or off-scale, the measurementswill linearly interpolate between known samples to make an “appropriate”guess as to the sample value. Missing samples at the ends of the measure-ment record wi...

Appendix B: Algorithms Appendices AĆ22 For example, if is set directly, then would not change even if samples were out of range. However, if was chosen using the % choice from the Set Levels in % Units selection of the Measure menu, then could give a “CLIPPING” warning. NOTE When measurements are di...

TDS 620A, 640A, & 644A User Manual AĆ23 Appendix C: Packaging for Shipment If you ship the digitizing oscilloscope, pack it in the original shipping cartonand packing material. If the original packing material is not available, packagethe instrument as follows: 1. Obtain a corrugated cardboard s...

TDS 620A, 640A, & 644A User Manual AĆ25 Appendix D: Factory Initialization Settings The factory initialization settings provide you a known state for the digitizingoscilloscope. Factory initialization sets values as shown in Table A-7. Table A-7: Factory Initialization Defaults Control Changed b...

TDS 520A, 524A, 540A, & 544A User Manual IndexĆ1 Index Numbers 1/seconds (Hz), Cursor menu, 3-21 100 MHz, Vertical menu, 3-149 20 MHz, Vertical menu, 3-149 A AC coupling, 2-16–2-17, Glossary-1 AC line voltage, trigger input, 2-14 AC, Main Trigger menu, 3-35 Accept Glitch, Main Trigger menu, 3-12...