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User Manual TDS 520A, 524A, 540A, & 544A Digitizing Oscilloscopes 070-8710-01 Please check for change information at the rear of this manual. First Printing: July 1993 Revised: November 1993.
Instrument Serial Numbers Each instrument manufactured by T ektronix has a serial number on a panel insert or tag, or stamped on the chassis. The first letter in the serial number designates the country of manufacture. The last five digits of the serial number are assigned sequentially and are unique to each instrument.
W ARRANTY T ektronix warrants that this product will be free from defects in materials and workmanship for a period of three (3) years from the date of shipment.
German Postal Information Certificate of the Manufacturer/Importer We hereby certify that the TDS 520A, TDS 524A, TDS 540A, and TDS 544A Oscilloscopes and all factory-installed options complies with the RF Interference Suppression requirements of Postal Regulation Vfg.
EC Declaration of Conformity We T ektronix Holland N.V . Marktweg 73A 8444 AB Heerenveen The Netherlands declare under sole responsibility that the TDS 520A, 524A, 540A, & 544A Digitizing Oscilloscopes meet the intent of Directive 89/336/EEC for Electromagnetic Compatibility .
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TDS 620A, 640A, & 644A User Manual W elcome 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.
Welcome Welcome In the Getting Started and Reference sections, you will find various proce- dures which contain steps of instructions for you to perform. T o keep those instructions clear and consistent, this manual uses the following conventions: In procedures, names of front panel controls and menu labels appear in boldface print.
TDS 520A, 524A, 540A, & 544A User Manual T able of Contents Safety v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Getting Started Product Description 1-1 . . . . . . . . . . . . . . . .
T able of Contents Contents File System (Optional on TDS 520A & TDS 540A) 3-55 . . . . . . . . . . . . . . Hardcopy 3-59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Help 3-67 . . . . . . . .
TDS 620A, 640A, & 644A 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.
Safety Safety Observe all of these precautions to ensure your personal safety and to pre- vent damage to either the digitizing oscilloscope or equipment connected to it.
Getting Started.
TDS 520A, 524A, 540A, & 544A User Manual Product Description Y our T ektronix digitizing oscilloscope is a superb tool for acquiring, displaying, and measuring waveforms. Its performance addresses the needs of both benchtop lab and portable applications with the following features: 500 MHz maximum analog bandwidth.
Product Description Getting Started.
TDS 620A, 640A, & 644A User Manual Start Up Before you use the digitizing oscilloscope, ensure that it is properly installed and powered on. T o ensure maximum accuracy for your most critical measurements, you should know about signal path compensation.
Start Up Getting Started 4. Check that you have the proper electrical connections. The digitizing oscilloscope requires 90 to 250 V AC 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 (see Figure 1-1) to the power system.
Start Up TDS 620A, 640A, & 644A User Manual 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 T est Check the self test results.
Getting Started Setting Up for the Examples All the examples use the same setup. Once you perform this setup, you do not have to change the signal connections for any of the other examples. Remove all probes and signal inputs from the input BNC connectors along the lower right of the front panel.
TDS 620A, 640A, & 644A User Manual Example 1: Displaying a W aveform 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.
Example 1: Displaying a W aveform Getting Started 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.
Example 1: Displaying a W aveform TDS 620A, 640A, & 644A User Manual Figure 1-7 shows the display that results from the instrument reset. There are several important points to observe: The trigger level bar shows that the waveform is triggered at a level near 50% of its amplitude (from step 4).
Example 1: Displaying a W aveform Getting Started The display shows the probe compensation signal. It is a 1 kHz square wave of approximately 0.5 V amplitude. Y ou can adjust the size and placement of the waveform using the front-panel knobs. Figure 1-8 shows the main VERTICAL and HORIZONT AL sections of the front panel.
Example 1: Displaying a W aveform TDS 620A, 640A, & 644A User Manual 1. T o create an unstable display , slowly turn the trigger MAIN LEVEL knob (see Figure 1-9) first one direction, then the other . Observe what happens when you move the trigger level above the highest part of the displayed waveform.
Example 1: Displaying a W aveform Getting Started Figure 1-1 1: The Display After Pressing Autoset NOTE If the corners on your displayed signal look rounded or pointed (see Figure 1-12), then you may need to compensate your probe. The Probe Compensation section on page 3-1 10 explains how to com- pensate your probe.
TDS 620A, 640A, & 644A User Manual Example 2: Multiple W aveforms In this example you learn how to display and control more than one waveform at a time.
Example 2: Multiple W aveforms Getting Started 3. Press AUT OSET . 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.
Example 2: Multiple W aveforms TDS 620A, 640A, & 644A User Manual Side Menu Title Ch2 Reference Indicator Figure 1-14: The V ertical 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.
Example 2: Multiple W aveforms Getting Started Side Menu Title Figure 1-15: The Menus After Changing Channels Pressing the W A VEFORM OFF button removes the waveform for the current- ly selected channel. If the waveform you want to remove is not already se- lected, select that channel using the channel ( CH ) button.
TDS 620A, 640A, & 644A User Manual Example 3: Automated Measurements In this example you learn how to use the automated measurement system to get numeric readouts of important waveform characteristics. T o use the automated measurement system, you must have a stable display of your signal.
Example 3: Automated Measurements Getting Started 5. If it is not already selected, press Select Measrmnt (main). The readout for that menu item indicates which channel the measurement will be taken from. All automated measurements are made on the selected channel.
Example 3: Automated Measurements TDS 620A, 640A, & 644A User Manual Press here to remove menus from screen. Figure 1-17: Four Simultaneous Measurement Readouts The Measure menu lets you remove measurements you no longer want displayed. Y ou can remove any one measurement, or you can remove them all with a single menu item.
Example 3: Automated Measurements Getting Started General Purpose Knob Setting and Readout Highlighted Menu Item with Boxed Readout V alue General Purpose Knob Icon Figure 1-18: General Purpose Knob Indicators There are several important things to observe on the screen: The knob icon appears at the top of the screen.
Example 3: Automated Measurements TDS 620A, 640A, & 644A User Manual 1. Press Low Ref (side). 2. On the numeric keypad, press the 2 , the 0 , and the ENTER ( ) but- tons, which sets the low measurement reference to 20%. Observe that the rise-time value has changed.
Example 3: Automated Measurements Getting Started The snapshot measurements do not continuously update. Snapshot executes a one-time capture of all measurements and does not update those measurements unless it is performed again. 2. Press Again (side) to do another snapshot and update the snapshot measurements.
TDS 620A, 640A, & 644A User Manual Example 4: Saving Setups This example shows you how to save all the settings of the digitizing oscillo- scope and how to recall the setup later to quickly re-establish the previously saved state. The oscilloscope provides several storage locations where you can save the setups.
Example 4: Saving Setups Getting Started Figure 1-20: Save/Recall Setup Menu 7. Press one of the T o Setup side menu buttons to store the current instru- ment settings into that setup location. Remember which setup location you selected for use later .
Operating Basics.
TDS 620A, 640A, & 644A User Manual Overview This section describes the basic concepts of operating the digitizing oscillo- scope. Understanding the basic concepts of your digitizing oscilloscope will help you use it much more effectively .
Overview Operating Basics.
TDS 620A, 640A, & 644A User Manual At a Glance The At a Glance section contains illustrations of the display , the front and rear panels, and the menu system. These will help you understand and operate the digitizing oscilloscope. This section also contains a visual guide to using the menu system.
At a Glance Operating Basics File System, page 3-55 (Optional on TDS 620A & TDS 640A) Hardcopy , page 3-59 Autoset, page 3-10 Help, page 3-67 Status, page 3-140 Selecting Channels, page 3-136 Hori.
At a Glance TDS 620A, 640A, & 644A User Manual Security Bracket GPIB Connector page 3-126 Centronics Connector (Optional on TDS 620A & TDS 640A) Principal Power Switch, page 1-3 Serial Number .
At a Glance Operating Basics 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 men.
At a Glance TDS 620A, 640A, & 644A User Manual 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).
At a Glance At a Glance Press to display pop-ups. Press it again to make selection. Alternatively , press SHIFT first to make selection in the opposite direction. Press here to remove menus from screen. A pop-up selection changes the other main menu titles.
At a Glance TDS 520A, 524A, 540A, & 544A User Manual 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.
At a Glance Operating Basics Measure Menu (see page 3-86) Save/Recall Setup Menu (see page 3-130) Save/Recall W aveform Menu (see page 3-133) More Menu (see page 3-159) Main Trigger Menu –Pulse (see.
At a Glance TDS 620A, 640A, & 644A User Manual Press these buttons: T o bring up these menus: Utility Menu – I/O – GPIB (see page 3-126) V ertical Channel Menu ( see page 3-147) Zoom Menu ( se.
At a Glance Operating Basics.
TDS 620A, 640A, & 644A User Manual T riggering This section describes the edge trigger of the main trigger system and ex- plores, in a general sense, the topic of triggering. This oscilloscope also has logic and pulse triggers in the main trigger system and a delayed trigger system.
T riggering Operating Basics AC Line V oltage — this trigger source is useful when you are looking at signals related to the power line frequency . Examples include devices such as lighting equipment and power supplies. Because the digitizing oscilloscope generates the trigger , you do not have to input a signal to create the trigger .
T riggering TDS 620A, 640A, & 644A User Manual Automatic — this trigger mode (auto mode) lets the oscilloscope acquire a waveform even if a trigger does not occur . Auto mode uses a timer that starts after a trigger event occurs. If another trigger event is not detected before the timer times out, the oscilloscope forces a trigger anyway .
T riggering Operating Basics Holdoff Holdof f Trigger Points Trigger Level Holdoff Acquisition Interval Acquisition Interval Triggers are Not Recognized During Holdof f Time Figure 2-2: T rigger Holdoff Time Ensures V alid T riggering Holdoff is settable from 0% (minimum holdof f available) to 100% (maximum available).
T riggering TDS 620A, 640A, & 644A User Manual The adjustable trigger position defines where on the waveform record the trigger occurs. It lets you properly align and measure data within records. The part of the record that occurs before the trigger is the pretrigger portion.
T riggering Operating Basics As mentioned earlier in this section there is also a delayed trigger system that provides an edge trigger (no pulse or logic triggers).
TDS 620A, 640A, & 644A User Manual Acquisition Acquisition is the process of sampling the analog input signal, converting it into digital data, and assembling it into a waveform record. The oscilloscope creates a digital representation of the input signal by sampling the voltage level of the signal at regular time intervals (Figure 2-4).
Acquisition Operating Basics 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.
Acquisition TDS 620A, 640A, & 644A User Manual If you focus on only one channel at the maximum possible real-time rate, the TDS 524A and TDS 620A oscilloscopes can acquire at 500 Megasamples/ second using both its digitizers, while the TDS 644A and TDS 640A oscillo- scopes can combine all four digitizers and acquire at 1 Gigasample/second.
Acquisition Operating Basics 1st Acquisition Cycle 3rd Acquisition Cycle nth Acquisition Cycle 2nd Acquisition Cycle Record Points Figure 2-7: Equivalent-Time Sampling The oscilloscope takes a few samples with each trigger event and eventually constructs a waveform record using the samples from multiple acquisitions.
Acquisition TDS 620A, 640A, & 644A User Manual T able 2-1: Sampling Mode Selection — 100 ns/Div to 50 ns/Div (When Fit to Screen is Off) Instrument and Number of Channels 100 ns/Div 50 ns/Div TD.
Acquisition Operating Basics Ground (GND) coupling disconnects the input signal from the acquisition. Input impedance lets you select either 1 M or 50 impedance. NOTE If you select 50 impedance with AC coupling, the digitizing oscillo- scope will not accurately display frequencies under 200 kHz.
TDS 620A, 640A, & 644A User Manual Scaling and Positioning W aveforms Scaling and positioning waveforms means increasing or decreasing their displayed size and moving them up, down, right, and left on the display .
Scaling and Positioning W aveforms Operating Basics Y ou can adjust the vertical position of the selected waveform by moving it up or down on the display . For example, when trying to compare multiple wave- forms, you can put one above another and compare them, or you can overlay the two waveforms on top of each other .
Scaling and Positioning W aveforms TDS 620A, 640A, & 644A User Manual Aliasing When aliasing happens, you see a waveform with a frequency lower than the actual waveform being input or a waveform is not stable even though the light next to TRIG’D is lit.
Scaling and Positioning W aveforms Operating Basics FastFrame TM Y ou can define and enable FastFrame TM (also called “segmented memory”) on the TDS 600A. This feature lets you capture multiple acquisitions in the acquisition memory of a single channel.
Scaling and Positioning W aveforms TDS 620A, 640A, & 644A User Manual See Autoset , on page 3-10. See Delayed T riggering , on page 3-22. See Horizontal Control , on page 3-68.
Operating Basics Measurements The digitizing oscilloscope not only displays graphs of voltage versus time, it also can help you measure the displayed information (see Figure 2-1 1).
Measurements TDS 620A, 640A, & 644A User Manual The snapshot selection in the Measurement menu lets you display almost all of the measurements at once. Y ou can read about snapshot under Snapshot of Measurements, on page 3-95. Automated measurements use readouts to show measurement status.
Measurements Operating Basics T racking mode cursors operate in tandem: you move both cursors at the same time using the general purpose knob. T o adjust the solid cursor relative to the dashed cursor , you push the SELECT button to suspend cursor tracking and use the general purpose knob to make the adjust- ment.
Reference.
TDS 620A, 640A, & 644A User Manual Overview This section describes the details of operating the digitizing oscilloscope. It contains an alphabetical list of tasks you can perform with the digitizing oscilloscope. Use this section to answer specific questions about instrument operation.
Overview Reference.
TDS 620A, 640A, & 644A User Manual Acquisition Modes The acquisition system has several options for converting analog data into digital form. The Acquisition menu lets you determine the acquisition mode, whether or not to permit equivalent time sampling, and how to start and stop acquisitions.
Acquisition Modes Reference 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 speed of a single acquisition.
Acquisition Modes TDS 620A, 640A, & 644A User Manual Hi Res Mode In Hi Res mode, the digitizing oscilloscope averages all samples taken during an acquisition interval to create a record point. That average results in a higher-resolution, lower-bandwidth waveform.
Acquisition Modes Reference After each trigger event, the oscilloscope acquires data and then compares the min/max values from the current acquisition with those stored from pre- vious acquisitions. The final display shows the most extreme values for all the acquisitions for each point in the waveform record.
Acquisition Modes TDS 620A, 640A, & 644A User Manual T o bring up the acquisition menu (Figure 3-2) press SHIFT ACQUIRE MENU . Acquisition Mode T o choose how the digitizing oscilloscope will create points in the waveform record: Press SHIFT ACQUIRE MENU ➞ Mode (main) ➞ Sample , Peak Detect , Hi Res , Envelope, or A verage (side).
Acquisition Modes Reference Figure 3-3: Acquire Menu — Stop After RUN/ST OP button only (side) lets you start or stop acquisitions by toggling the RUN/STOP button. Pressing the RUN/STOP button once will stop the acquisitions. The upper left hand corner in the display will say Stopped and show the number of acquisitions.
Acquisition Modes TDS 620A, 640A, & 644A User Manual Limit T est Condition Met (side) lets you acquire waveforms until wave- form data exceeds the limits specified in the limit test.
Reference Autoset The autoset function lets you quickly obtain and display a stable waveform of usable size. Autoset automatically sets up the front panel controls based on the characteristics of the input signal. It is much faster and easier than a manual control-by-control setup.
Autoset TDS 620A, 640A, & 644A User Manual T able 3-2: Autoset Defaults Control Changed by Autoset to Selected channel Numerically lowest of the displayed channels Acquire Mode Sample Acquire Repe.
Reference Color (TDS 524A & TDS 644A) The TDS 524A & TDS 644A can display information in different colors. The Color menu lets you choose palettes of colors and decide what colors to assign to what pieces of information. T o bring up the Color menu: 1.
Color TDS 620A, 640A, & 644A User Manual Choose Palette Y ou 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.
Color Reference ScrTxt Figure 3-5: Display Menu — Palette Colors 2. Select one of the 13 colors by pressing (repeatedly) Color in the side menu. 3. If you want to use the factory default for this color , press the side menu Reset to Factory Color . 4.
Color TDS 620A, 640A, & 644A User Manual 3. If you want to assign the selected math waveform to a specific color , press Color and cycle through the choices. 4. If you want the selected math waveform to be the same color as the waveform it is based on, select Color Matches Contents .
Color Reference Select Options T o define what color to show where a waveform crosses another waveform: 1. Press the Options main menu item. 2. Select that you wish to use a special color to mark collision zones by toggling Collision Contrast in the side menu to ON .
TDS 620A, 640A, & 644A User Manual Cursor Measurements Use the cursors to measure the difference (either in time or voltage) between two locations in a waveform record. Cursors are made up of two markers that you position with the general pur- pose knob.
Cursor Measurements Reference NOTE When cursors measure certain math waveforms, the measurement may not be of time, frequency , or voltage. Cursor measurement of those math waveforms that are not of time, frequency , or voltage is described in Waveform Math, which begins on page 3-159.
Cursor Measurements TDS 620A, 640A, & 644A User Manual In FastFrame mode, the @ shows the time position of the selected cursor relative to the trigger point of the frame that the selected cursor is in. The shows the time difference between the two cursors only if both cursors are in the same frame.
Cursor Measurements Reference Non-selected Cursor (Dashed V ertical Bar) Cursor Readout (Paired) Selected Cursor (Solid V ertical Bar) Position of V ertical Bar Cursors (Useful for Locating Cursors Outside the Display) Figure 3-1 1: Paired Cursor Menu and Readouts Mode Select the cursor mode you want using the Mode menu item.
Cursor Measurements TDS 620A, 640A, & 644A User Manual Time Units Y ou can choose to display vertical bar cursor results in units of time or fre- quency . If you have Option 5 V ideo, you can also display the results in terms of video line number .
Reference Delayed T riggering The TDS 600A Series oscilloscopes provide a main time base and a delayed time base. The delayed time base, like the main time base, requires a trigger signal and an input source dedicated to that signal. Y ou can only use delay with respect to the main edge trigger and certain classes of main pulse trig- gers.
Delayed T riggering TDS 620A, 640A, & 644A User Manual After Time waits the user-specified time, then waits for the next delayed trigger event, and then acquires. After Events waits for the specified number of delayed trigger events and then acquires.
Delayed T riggering Reference Time Delay (From Delay Trig Menu) Time Delay (From Delay Trig Menu) Start Posttrigger Acquisition (T rigger on nth Delayed Trigger Event) Time Delay (From Horiz Menu) Tim.
Delayed T riggering TDS 620A, 640A, & 644A User Manual Delayed T riggerable Y ou must make sure that the Main Trigger menu settings are compatible with Delayed T riggerable. 1. Press TRIGGER MENU . 2. If T ype is set to Logic , press T ype (main) to change it to either Edge or Pulse as fits your application.
Delayed T riggering Reference The Source menu lets you select which input will be the delayed trigger source. 7. Press Source (main) ➞ Ch1, Ch2, Ch3 ( Ax1 on the TDS 524A & TDS 620A), Ch4 ( Ax2 on the TDS 524A & TDS 620A), or Auxiliary (not available on the TDS 524A & TDS 620A) (side).
Delayed T riggering TDS 620A, 640A, & 644A User Manual NOTE When you set the V ertical SCALE smaller than 200 mV , the oscillo- scope reduces the Set to TTL or Set to ECL trigger levels below standard TTL and ECL levels. That happens because the trigger level range is fixed at center .
Reference Display Modes The digitizing oscilloscope can display waveform records in different ways. The Display menu lets you adjust the oscilloscope display style, intensity level, graticule, and format. T o bring up the Display menu: 1. Press DISPLA Y to show the Display menu.
Display Modes TDS 620A, 640A, & 644A User Manual V ectors has the display draw vectors (lines) between the record points. Dots display waveform record points as dots.
Display Modes Reference Display Readout Readout options control whether the trigger indicator , trigger level bar , and current date and time appear on the display . The options also control what style trigger level bar , long or short, is displayed. 1.
Display Modes TDS 620A, 640A, & 644A User Manual Filter T ype The display filter types are sin(x)/x interpolation and linear interpolation. For more information see the Concepts section, page 2-21. Press DISPLA Y ➞ Filter (main) ➞ Sin(x)/x Interpolation or Linear Interpo- lation (side).
Display Modes Reference XY format compares the voltage levels of two waveform records point by point. That is, the digitizing oscilloscope displays a graph of the voltage of one waveform record against the voltage of another waveform record. This mode is particularly useful for studying phase relationships.
Display Modes TDS 620A, 640A, & 644A User Manual See Acquisition, on page 2-19. See Color , on page 3-12. See Measurements, on page 2-30. For More Information.
Reference Edge T riggering An edge trigger event occurs when the trigger source passes through a specified voltage level in a specified direction (the trigger slope). Y ou will likely use edge triggering for most of your measurements. Y ou can select the edge source, coupling, slope, level, and mode (auto or normal).
Edge T riggering TDS 620A, 640A, & 644A User Manual Figure 3-19: Main T rigger Menu — Edge T ype Coupling T o select the coupling you want: Press TRIGGER MENU ➞ T ype (main) ➞ Edge (pop-up) ➞ Cou- pling (main) ➞ DC , AC , HF Rej , LF Rej , or Noise Rej (side).
Edge T riggering Reference Slope T o select the slope that the edge trigger will occur on: 1. Press the TRIGGER MENU ➞ T ype (main) ➞ Edge (pop-up) ➞ Slope (main).
Edge T riggering TDS 620A, 640A, & 644A User Manual Mode & Holdoff Y ou can change the holdoff time and select the trigger mode using this menu item. See T riggering on page 2-13 for more details. 1. Press the TRIGGER MENU ➞ Mode & Holdoff (main) ➞ Auto or Nor- mal (side).
Reference Fast Fourier T ransforms Advanced DSP Math (optional on TDS 620A & TDS 640A), provides the Fast Fourier T ransform (FFT). The FFT allows you to transform a waveform from a display of its amplitude against time to one that plots the amplitudes of the various discrete frequencies the waveform contains.
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual zontal scale for FFT math waveforms is always expressed in frequency per division with the beginning (left-most point) of the waveform representing zero frequency (DC).
Fast Fourier T ransforms Reference Figure 3-21: Define FFT W aveform Menu 5. If the selected math waveform is not FFT , press Change Math Definition (side) ➞ FFT (main). See Figure 3-21. 6. Press Set FFT Source to (side) repeatedly until the channel source selected in step 1 appears in the menu label.
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Hamming — V ery good window for resolving frequencies that are very close to the same value with somewhat improved amplitude accuracy over the rectangular window . Hanning — V ery good window for measuring amplitude accuracy but degraded for resolving frequencies.
Fast Fourier T ransforms Reference Cursor Measurements of an FFT Once you have displayed an FFT math waveform, use cursors to measure its frequency amplitude or phase angle. 1. Be sure MORE is selected in the channel selection buttons and that the FFT math waveform is selected in the More main menu.
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Figure 3-23: Cursor Measurement of an FFT W aveform 10. Press Function (main) ➞ Paired (side). 1 1. Use the technique just outlined to place the vertical bar of each paired cursor to the points along the horizontal axis you are interested in.
Fast Fourier T ransforms Reference The FFT Frequency Domain Record The following topics discuss the relation of the source waveform to the record length, frequency resolution, and frequency range of the FFT frequency domain record. (The FFT frequency domain waveform is the FFT math waveform that you display .
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Zero Phase Reference W aveform Record > 10 K W aveform Record ≤ 10 K FFT Time Domain Record = Waveform Record Zero Phase Reference FFT Time Domain Record = 10k Figure 3-24: W aveform Record vs.
Fast Fourier T ransforms Reference Where: F is the frequency resolution. Sample Rate is the sample rate of the source waveform. FFT Length is the length of the FFT Time Domain wave- form record.
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Record Length Most often, you will want to use a short record length because more of the FFT waveform can be seen on screen and long record lengths can slow oscilloscope response.
Fast Fourier T ransforms Reference Zoom always uses either sin(x)/x or linear interpolation when expanding displayed waveforms. T o select the interpolation method: press DISPLA Y ➞ Setting (main) .
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Nyquist Frequency Point Frequency Aliased Frequencies Actual Frequencies Figure 3-26: How Aliased Frequencies Appear in an FFT Considera.
Fast Fourier T ransforms Reference For records with a 15 K length, set the trigger position to 33%. Use the horizontal position knob to move the trigger T on screen to the center horizontal graticule line.
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Windowing Process — The oscilloscope multiplies the FFT time domain record by one of four FFT windows before it inputs the record to the FFT function. Figure 3-27 shows how the time domain record is processed.
Fast Fourier T ransforms Reference FFT Time Domain Record FFT Time Domain Record After Windowing FFT Window FFT Frequency Domain Record FFT Xs Figure 3-27: Windowing the FFT T ime Domain Record Y ou c.
Fast Fourier T ransforms TDS 620A, 640A, & 644A User Manual Window Characteristics — When evaluating a window for use, you may want to examine how it modifies the FFT time domain data. Figure 3-28 shows each window , its bandpass characteristic, bandwidth, and highest side lobe.
Fast Fourier T ransforms Reference Rectangular Window Hanning Window Hamming Window Blackman-Harris Window FFT Window T ype Bandpass Filter 0.89 -3 dB Bandwidth Highest Side Lobe 1.
TDS 620A, 640A, & 644A User Manual File System (Optional on TDS 620A & TDS 640A) The File Utilities menu, which comes with the Hardcopy , Save Setup, and Save W aveforms menus, gives you a variety of features for managing the floppy disk.
File System Reference NOTE The amount of free space on the disk is shown in the upper right corner of the display . The digitizing oscilloscope shows the amount in K bytes. T o convert the amount to bytes, you simply multiply the K bytes amount times 1024.
File System TDS 620A, 640A, & 644A User Manual Figure 3-30: File System — Labelling Menu Copy T o copy a file or directory , turn the general purpose knob until it scrolls the cursor over the name of the file to copy . Then, press the side menu Copy button.
File System Reference The labelling menu should appear . T urn the general purpose knob or use the main-menu arrow keys to select each letter . Press Enter Char from the main menu to enter each letter . When you have entered the name, press the side menu OK Accept item.
TDS 520A, 524A, 540A, & 544A User Manual Hardcopy Y ou can get a copy of the digitizing oscilloscope display by using the hardco- py feature. Depending on the output format you select, you create either an image or a plot. Images are direct bit map representations of the digitizing oscilloscope display .
Hardcopy Reference Before you make a hardcopy , you need to set up communications and hard- copy parameters. This discussion assumes that the hardcopy device is already connected to the GPIB port on the rear panel. If that is not the case see Connection Strategies on page 3-63.
Hardcopy TDS 520A, 524A, 540A, & 544A User Manual Setting Hardcopy Parameters T o specify the hardcopy format, layout, and type of port using the hardcopy menu: 1.
Hardcopy Reference T o stop and discard the hardcopy being sent, press HARDCOPY again while the hardcopy in process message is still on screen. T o add additional hardcopies to the printer spool, press HARDCOPY again after the hardcopy in process message is removed from the screen.
Hardcopy TDS 520A, 524A, 540A, & 544A User Manual Date and Time Display Figure 3-33: Date and Time Display 5. Use the general purpose knob or the keypad to set the parameter you have chosen to the value desired. (The format when using the keypad is day .
Hardcopy Reference Strategies for actually printing a copy include: Send output straight to a printer/plotter . Send the data to a computer to print from there and/or to import into your favorite desktop publishing or other application package.
Hardcopy TDS 520A, 524A, 540A, & 544A User Manual GPIB Cable Digitizing Oscilloscope PC Compatible Centronics or RS-232 Cable Hardcopy Device Figure 3-35: Connecting the Digitizing Oscilloscope an.
Hardcopy Reference 5. T ype: IBRDF <Filename> where <Filename> is a valid DOS file name you want to call your hardcopy information. It should be 8 characters long with up to a 3 character extension. For example, you could type “ibrdf screen1” .
TDS 620A, 640A, & 644A User Manual Help The on-line help system provides brief information about each of the digitizing oscilloscope controls. T o use the on-line help system: Press HELP to provide on-screen information on any front panel button, knob or menu item (see Figure 3-36).
Reference Horizontal Control Y ou can control the horizontal part of the display (the time base) using the horizontal menu and knobs. By changing the horizontal scale, you can focus on a particular portion of a waveform. By adjusting the horizontal position, you can move the waveform right or left to see different portions of the waveform.
Horizontal Control TDS 620A, 640A, & 644A User Manual At the top of the display , the Record View shows the size and location of the waveform record and the location of the trigger relative to the display (see Figure 3-38).
Horizontal Control Reference Y ou also can select Delayed Runs After Main or Delayed T riggerable . For more information on how to use these two menu items, see Delayed T rigger- ing on page 3-22.
Horizontal Control TDS 620A, 640A, & 644A User Manual Y ou can also control whether changing the horizontal position setting affects all displayed waveforms, just the live waveforms, or only the selected wave- form.
Horizontal Control Reference 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.
TDS 620A, 640A, & 644A User Manual Limit T esting Limit testing provides a way to automatically compare each incoming or math waveform against a template waveform. Y ou set an envelope of limits around a waveform and let the digitizing oscilloscope find waveforms that fall outside those limits (see Figure 3-40).
Limit T esting Reference NOTE The template will be smoother if you acquire the template waveform using A verage 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.
Limit T esting TDS 620A, 640A, & 644A User Manual If you wish to create another limit test template, store it in another des- tination to avoid overwriting the template you have just created. If you wish to view the template you have created, press the MORE button.
Limit T esting Reference If you want to send a hardcopy command when waveform data exceeds the limits set, toggle Hardcopy if Condition Met (side) to ON . Y ou can set the hardcopy system to send the hardcopy to the file system (optional on the TDS 620A & TDS 640A).
Limit T esting TDS 620A, 640A, & 644A User Manual Multiple W aveform Comparisons When comparing one or more waveforms, each against a common template or against its own template, consider the foll.
Reference Logic T riggering 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 F ALSE).
Logic T riggering TDS 620A, 640A, & 644A User Manual At the bottom of the display , the T rigger readout shows some of the key parameters of the logic trigger (see Figure 3-42).
Logic T riggering Reference T able 3-4: Logic T riggers Pattern State Definition 1,2 AND Clocked AND If all the preconditions selected for the logic inputs 3 are true, then the oscilloscope triggers. NAND Clocked NAND If not all of the preconditions se- lected for the logic inputs 3 are true, then the oscilloscope trig- gers.
Logic T riggering TDS 620A, 640A, & 644A User Manual Figure 3-43: Logic T rigger Menu T rigger When This menu item lets you determine if the oscilloscope will trigger when the logic condition is met ( Goes TRUE ) or when the logic condition is not met ( Goes F ALSE ).
Logic T riggering Reference Mode & Holdoff Y ou can change the holdoff time and select the trigger mode using this menu item. 1. Press TRIGGER MENU ➞ T ype (main) ➞ Logic (pop-up) ➞ Class (main) ➞ Pattern or State (pop-up) ➞ Mode & Holdoff (main) ➞ Auto or Normal (side).
Logic T riggering TDS 620A, 640A, & 644A User Manual Define a T ime Qualified Pattern T rigger Y ou can also time qualify a pattern logic trigger . That is, you specify a time that the boolean logic function (AND, NAND, OR, or NOR) must be TRUE (logic high).
Logic T riggering Reference Logic Function (AND) Becomes TRUE Logic Function Becomes F ALSE and Triggers Acquisition Time Logic Function is TRUE Time Logic Function Must be TRUE Figure 3-44: Logic T r.
Logic T riggering TDS 620A, 640A, & 644A User Manual Define Logic T o choose the type of logic function you want applied to the input channels: Press TRIGGER MENU ➞ T ype (main) ➞ Logic (pop-up) ➞ Class (main) ➞ State (pop-up) ➞ Define Logic (main) ➞ AND , OR , NAND , or NOR (side).
Reference Measurement System There are various ways to measure properties of waveforms. Y ou can use graticule, cursor , or automatic measurements. This section describes auto- matic measurements ; cursors and graticules are described elsewhere. (See Cursor Measurements on page 3-17 and Measurements on page 2-30.
Measurement System TDS 620A, 640A, & 644A User Manual T able 3-5: Measurement Definitions (Cont.) Name Definition Delay T iming measurement. The time between the MidRef crossings of two different traces or the gated region of the traces. Fall Time T iming measurement.
Measurement System Reference T able 3-5: Measurement Definitions (Cont.) Name Definition Period T iming measurement. T ime it takes for the first complete signal cycle to happen in the waveform or gated region. The reciprocal of frequency . Measured in seconds.
Measurement System TDS 620A, 640A, & 644A User Manual The readout area for measurements is on the right side of the waveform window . Y ou can display and continuously update as many as four measure- ments at any one time. When menus are displayed, the readouts appear in the graticule area.
Measurement System Reference T o vary the source for measurements, simply select the other channel and then choose the measurements you want. Be careful when taking automatic measurements on noisy signals. Y ou might measure the frequency of the noise and not the desired waveform.
Measurement System TDS 620A, 640A, & 644A User Manual Gated Measurements The gating feature lets you limit measurements to a specified portion of the waveform. When gating is Off , the oscilloscope makes measurements over the entire waveform record.
Measurement System Reference NOTE Cursors are displayed relative to the selected waveform. If you are making a measurement using two waveforms, this can be a source of confusion.
Measurement System TDS 620A, 640A, & 644A User Manual 2. Press High Ref , Mid Ref , Low Ref , or Mid2 Ref (side). High Ref — Sets the high reference level. The default is 90%. Mid Ref — Sets the middle reference level. The default is 50%. Low Ref — Sets the low reference level.
Measurement System Reference 2. Press Measure Delay to (side) repeatedly to choose the delay to wave- form. The choices are Ch1 , Ch2 , Ch3, Ch4 (on the TDS 644A & TDS 640A); Ch1, Ch2, Ax1 , Ax2 (on the TDS 524A & TDS 620A); and Math1 , Math2 , Math3 , Ref1 , Ref2 , Ref3 , and Ref4.
Measurement System TDS 620A, 640A, & 644A User Manual Creating the Delay Measurement — Once you have specified the waveforms you are measuring between and which edges to use, you need to notify the digitizing oscilloscope to proceed with the measurement.
Measurement System Reference T o use snapshot, obtain a stable display of the waveform to be measured. Pressing AUTOSET may help. 1. Press MEASURE ➞ SNAPSHOT (main). 2. Press either SNAPSHOT (main) or AGAIN (side) to take another snap- shot. NOTE The snapshot display tells you the channel that the snapshot is being made on.
TDS 520A, 524A, 540A, & 544A User Manual Probe Accessories The probe you use and how you connect it to a signal source affect the oscilloscope acquisition of the waveform record. T wo important factors are ground lead inductance (introduced by the probe) and the physical layout of your circuit and component devices.
Probe Accessories Reference 4 Inch Ground Lead Low-Inductance Ground Lead Figure 3-52: Signal V ariation Introduced by Probe Ground Lead (1 ns/division) The following descriptions explain how to use many of the accessories that came with your probe. Figure 3-53 shows both standard and optional probe accessories and how they attach to your probe.
Probe Accessories TDS 520A, 524A, 540A, & 544A User Manual Marker Ring (Standard) Marker Ring (Standard) IC Protector Tip (Optional) Dual Lead Adapter (Optional) Probe Tip-to-Circuit Board Adapter.
Probe Accessories Reference Marker Rings The marker rings help you keep track of individual probes and signal sources when you have a complicated test setup. Use the marker rings whenever you want to identify a particular probe. Long Ground Leads Use long ground leads when a long reach is important and high-frequency information is not.
Probe Accessories TDS 520A, 524A, 540A, & 544A User Manual Probe-Tip-to-Circuit Board Adapters The probe-tip-to-circuit board adapters let you design minimum inductance test points into your next circuit board. That adapter provides maximum performance for the probe, because it virtually eliminates ground inductance effects.
Probe Accessories Reference Probe-Tip-to-Chassis Adapter The probe-tip-to-chassis adapter makes your test point accessible without removing instrument covers or panels.
Probe Accessories TDS 520A, 524A, 540A, & 544A User Manual Dual-Lead Adapter The dual-lead adapter makes an easy connection to 0.025 diameter connec- tor pins (see Figure 3-54). One lead connects to a ground reference pin, and the other to the signal pin.
Reference Probe Cal This oscilloscope lets you compensate the entire signal path, from probe tip to digitized signal, to improve the gain and offset accuracy of the probe. By executing Probe Cal on a channel with its probe installed, you can optimize the oscilloscope capability to make accurate measurements using that chan- nel and probe.
Probe Cal TDS 620A, 640A, & 644A User Manual 1. Install the probe on the input channel on which it is to be used. 2. Power on the digitizing oscilloscope and allow a 20 minute warm-up before doing this procedure. 3. Press SHIFT UTILITY ➞ System (main) ➞ Cal (pop-up).
Probe Cal Reference Figure 3-55: Probe Cal Menu and Gain Compensation Display 1 1. If the Probe Offset Compensation message is displayed, continue with step 15; otherwise, continue with step 12. 12. If the Compensation Error message is displayed, continue with step 13; otherwise continue with step 18.
Probe Cal TDS 620A, 640A, & 644A User Manual 19. If desired, repeat this procedure beginning at step 1 to compensate for other probe/channel combinations.
Probe Cal Reference Figure 3-56: Re-use Probe Calibration Data Menu If the Re-use Probe Calibration data? menu is displayed, you can choose one of the following options: Press OK Use Existing Data (side) to use the Probe Cal data last stored to compensate the probe.
Probe Cal TDS 620A, 640A, & 644A User Manual T able 3-6: Probe Cal Status Probe User T ype Probe Connected 2 Cal’d? 1 Action Simple Interface 3 Complex Interface 4 No Doesn’t Matter Initialize.
Reference Probe Compensation Passive probes require compensation to ensure maximum distortion-free input to the digitizing oscilloscope and to avoid high frequency amplitude errors (see Figure 3-57).
Probe Compensation TDS 620A, 640A, & 644A User Manual 4. If you need to change the input impedance, press Coupling (main). Then toggle the side menu selection to get the correct impedance. 5. Press SHIFT ACQUIRE MENU ➞ Mode (main) ➞ Hi Res (side).
Reference Probe Selection The probes included with your digitizing oscilloscope are useful for a wide variety of tasks. However , for special measurement situations you sometimes need different probes. This section helps you select the right probe for the job.
Probe Selection TDS 620A, 640A, & 644A User Manual Low Impedance (Z O ) Probes Low impedance probes measure frequency more accurately than general purpose probes, but they make less accurate amplitude measurements. They offer a higher bandwidth to cost ratio.
Probe Selection Reference Active voltage probes, sometimes called “FET” probes, use active circuit elements such as transistors. There are three classes of active probes: High speed active Differe.
Probe Selection TDS 620A, 640A, & 644A User Manual amplifiers) to precisely connect your instrument to your device-under-test. These probes have the same electrical characteristics as high speed, active probes but use a smaller mechanical design.
Probe Selection Reference Optical probes let you blend the functions of an optical power meter with the high-speed analog waveform analysis capability of an oscilloscope. Y ou have the capability of acquiring, displaying, and analyzing optical and electrical signals simultaneously .
Probe Selection TDS 620A, 640A, & 644A User Manual T able 3-7 lists TDS 600A compatible probes classified by type. T able 3-7: TDS 600A Compatible Probes Probe T ype T ektronix Model Description Passive, high impedance voltage P6139A (std.) P6101A 10X, 500 MHz 1X, 15 MHz Passive, SMD P6563AS 20X, 500 MHz Passive, low impedance Z O P6156 10X, 3.
Probe Selection Reference Another way to classify probes is by application. Different applications de- mand different probes. Use T able 3-8 to select a probe for your application.
TDS 620A, 640A, & 644A User Manual Pulse T riggering Pulse triggering can be very useful. For example, you might be testing a product with a glitch in the power supply . The glitch appears once a day . So instead of sitting by and waiting for it to appear , you can use pulse triggering to automatically capture your data.
Pulse T riggering Reference T able 3-9: Pulse T rigger Definitions Name Definition Glitch positive T riggering occurs if the oscilloscope detects positive spike widths less than the specified glitch time. Glitch negative T riggering occurs if the oscilloscope detects negative spike widths less than the specified glitch time.
Pulse T riggering TDS 620A, 640A, & 644A User Manual The pulse trigger menus let you define the pulse source, select the mode (auto or normal), and adjust the holdoff. T o bring up the Pulse T rigger menu: Press TRIGGER MENU ➞ T ype (main) ➞ Pulse (pop-up) ➞ Class (main) ➞ Glitch , Runt , or Width (pop-up) (see Figure 3-62).
Pulse T riggering Reference In Normal mode the oscilloscope acquires a waveform only if there is a valid trigger . (Y ou can force a single acquisition by pressing FORCE TRIGGER .) 2. T o change the holdoff time, press Holdoff (side). Use the general pur- pose knob or the keypad to enter the value in percent.
Pulse T riggering TDS 620A, 640A, & 644A User Manual If you select Set to 50% , you cause the digitizing oscilloscope to search for the point halfway between the peaks of the trigger source signal and set the trigger level to that point.
Pulse T riggering Reference Selected Trigger Bar at Upper Threshold Runt Pulse Crosses First Threshold Only , Recrosses First Threshold Level, and Triggers Acquisition Unselected T rigger Bar at Lower Threshold Figure 3-63: Main T rigger Menu—Runt Class Thresholds T o set the two threshold levels used in detecting a runt pulse: 1.
Pulse T riggering TDS 620A, 640A, & 644A User Manual Regardless of the polarity setting, triggering occurs at the point the runt pulse recrosses its first threshold. When you select the pulse class Width , the oscilloscope will trigger on a pulse narrower (or wider) than some specified range of time (defined by the upper limit and lower limit).
Reference Remote Communication Y ou may want to integrate your oscilloscope into a system environment and remotely control your oscilloscope or exchange measurement or waveform data with a computer . Y ou can control your oscilloscope remotely via the IEEE Std 488.
Remote Communication TDS 620A, 640A, & 644A User Manual GPIB Device GPIB Device GPIB Device GPIB Device GPIB Device GPIB Device GPIB Device Figure 3-64: T ypical GPIB Network Configuration Cables — An IEEE Std 488.1–1987 GPIB cable (available from T ektronix, part number 012–0991–00) is required to connect two GPIB devices.
Remote Communication Reference T o set up remote communications, ensure that your oscilloscope is physically cabled to the controller and that the oscilloscope parameters are correctly set. Plug an IEEE Std 488.2–1987 GPIB cable into the GPIB connector on the oscilloscope rear panel and into the GPIB port on your controller (see Fig- ure 3-66).
Remote Communication TDS 620A, 640A, & 644A User Manual GPIB Configuration Menu Figure 3-67: Utility Menu See Hardcopy , on page 3-59. See the TDS Family Digitizing Oscilloscopes Programmer Manual .
Reference Saving and Recalling Setups Y ou may want to save and reuse setups for many reasons. For example, after changing the setting during the course of an experiment, you may want to quickly return to your original setup. Y ou can save and recall up to ten instru- ment setups from internal oscilloscope memory .
Saving and Recalling Settings TDS 620A, 640A, & 644A User Manual T o store a setup to disk (optional on the TDS 620A & TDS 640A), press To File . Then use the general purpose knob to select the exact file from the resulting scrollbar list. Finally , press the side-menu Save T o Selected File to complete the operation.
Saving and Recalling Setups Reference If the checksum calculation is unsuccessful, displays a warning message; if the checksum calculation is successful, displays a confirmation mes- sage. Running File Utilities T o run file utilities (optional on the TDS 620A & TDS 640A), see the File System article on page 3-55.
TDS 620A, 640A, & 644A User Manual Saving and Recalling W aveforms Y ou can store a waveform in any of the four internal reference memories of the digitizing oscilloscope. That information is retained even when you turn the oscilloscope off or unplug it.
Saving and Recalling W aveforms Reference Figure 3-69: Save W aveform Menu Deleting W aveforms Y ou 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 ).
Saving and Recalling W aveforms TDS 620A, 640A, & 644A User Manual resulting scrollbar list. Only files with .WFM extensions are displayed. Finally , press from the side-menu T o Ref1 , T o Ref2 , T o Ref3, or T o Ref4 choices to complete the operation.
Reference Selecting Channels The selected channel is the channel that the digitizing oscilloscope applies all waveform-specific activities to (such as measurements or vertical scale and position). The channel readout shows the selected channel in inverse video in the lower left corner of the display .
Selecting Channels TDS 620A, 640A, & 644A User Manual T o 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. Y ou do not use the channel selection buttons when triggering.
Reference Signal Path Compensation This oscilloscope lets you compensate the internal signal path used to acquire the waveforms you acquire and measure. By executing the signal path com- pensation feature (SPC), you can optimize the oscilloscope capability to make accurate measurements based on the ambient temperature.
Signal Path Compensation TDS 620A, 640A, & 644A User Manual Figure 3-73: Performing a Signal Path Compensation.
Reference Status The Status menu lets you see information about the oscilloscope state. T o operate the Status menu: Press SHIFT ST A TUS ➞ Status (main) ➞ System , Display , T rigger , W aveforms , or I/O (side). Note: some oscilloscopes do not have a main Status menu.
Status TDS 620A, 640A, & 644A User Manual T o display the banner (firmware version, options, copyright, and patents): NOTE Some TDS 644A oscilloscopes do not have a Status main menu with a banner . However , all instruments display the banner briefly at power-on.
Reference T riggering T riggers determine when the digitizing oscilloscope starts acquiring and displaying a waveform. The TDS 600A has four types of trigger: edge, logic, pulse, and, with option 5, video.
T riggering TDS 620A, 640A, & 644A User Manual T o Set to 50% Y ou can quickly obtain an edge or pulse trigger (except for the Runt class) by pressing SET LEVEL TO 50%. The oscilloscope sets the trigger level to the halfway point between the peaks of the trigger signal.
T riggering Reference When READY is lighted, it means the digitizing oscilloscope can accept a valid trigger event, and the digitizing oscilloscope is waiting for that event to occur . When ARM is lighted, it means the trigger circuitry is filling the pretrigger portion of the waveform record.
T riggering TDS 620A, 640A, & 644A User Manual The trigger point indicator shows position. It can be positioned horizontally off screen, especially with long record length settings.
T riggering Reference See the Option 05 Video T rigger Interface Instruction Manual , T ektronix part number 070–8748–00..
TDS 620A, 640A, & 644A User Manual V ertical Control Y ou can control the vertical position and scale of the selected waveform using the vertical menu and knobs. By changing the vertical scale, you can focus on a particular portion of a waveform. By adjusting the vertical position, you can move the waveform up or down on the display .
V ertical Control Reference V ertical Readout Figure 3-79: V ertical Readouts and Channel Menu Coupling T o choose the type of coupling for attaching the input signal to the vertical attenuator for the selected channel and to set its input impedance: Press VERTICAL MENU ➞ Coupling (main) ➞ DC , AC , GND , or (side).
V ertical Control TDS 620A, 640A, & 644A User Manual Bandwidth T o eliminate the higher frequency components, change the bandwidth of the selected channel: Press VERTICAL MENU ➞ Bandwidth (main) ➞ Full , 100 MHz , or 20 MHz (side).
Reference W aveform Differentiation Advanced DSP Math (optional on TDS 620A & TDS 640A), provides wave- form differentiation that allows you to display a derivative math waveform that indicates the instantaneous rate of change of the waveform acquired.
W aveform Differentation TDS 620A, 640A, & 644A User Manual Derivative Math Waveform Source Waveform Figure 3-80: Derivative Math W aveform 5. Press Set Function to (side). Repeatedly press the same button (or use the general purpose knob) until diff appears in the menu label.
W aveform Differentation Reference Figure 3-81: Peak-Peak Amplitude Measurement of a Derivative W aveform Cursor Measurement of a Derivative W aveform Y ou can also use cursors to measure derivative waveforms. Use the same procedure as is found under Waveform Integration on page 3-155.
W aveform Differentation TDS 620A, 640A, & 644A User Manual When using the vertical scale knob to scale the source waveform, note that it also scales your derivative waveform.
Reference W aveform Integration Advanced DSP Math (optional on TDS 620A & TDS 640A), provides wave- form integration that allows you to display an integral math waveform that is an integrated version of the acquired waveform.
W aveform Integration TDS 620A, 640A, & 644A User Manual 5. Press Set Function to (side). Repeatedly press the same button until intg appears in the menu label. 6. Press OK Create Math W aveform (side) to turn on the integral math waveform. Y ou should now have your integral math waveform on screen.
W aveform Integration Reference 6. Read the integrated voltage over time between the cursors in volt- seconds from the : readout. Read the integrated voltage over time between the selected cursor and the reference indicator of the math waveform from the @: readout.
W aveform Integration TDS 620A, 640A, & 644A User Manual Read the integrated voltage over time between the X of the selected cursor and the reference indicator of the math waveform from the @: readout. Read the time difference between the long vertical bars of the paired cursors from the : readout.
W aveform Integration Reference Zoom Once you have your waveform optimally displayed, you may magnify (or reduce) it vertically and horizontally to inspect any feature you desire. Just be sure the integrated waveform is the selected waveform. (Press MORE , then select the integrated waveform in the More main menu.
TDS 620A, 640A, & 644A User Manual W aveform Math Y ou can mathematically manipulate your waveforms. For example, you might have a waveform clouded by background noise. Y ou can obtain a cleaner waveform by subtracting the background noise from your original waveform.
W aveform Math Reference NOTE If your digitizing oscilloscope is equipped with Advanced DSP Math (optional on TDS 620A & TDS 640A), the menu item FFT will be at the same brightness as the menu items Single Wfm Math and Dual Wfm Math ; otherwise, FFT will be dimmed.
W aveform Math TDS 620A, 640A, & 644A User Manual Figure 3-85: Dual W aveform 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 Zoom At times, you may want to expand or compress a waveform on the display without changing the acquisition parameters. Y ou can do that with the zoom feature. When you zoom in on a waveform on the display , you expand a portion of the waveform.
Zoom TDS 620A, 640A, & 644A User Manual NOTE Although zoom must be turned on to control which waveforms zoom affects, the setting for Horizontal Lock affects which waveforms the horizontal control positions whether zoom is on or off. The rules for the three settings are listed in step 2.
Zoom Reference Reset Zoom T o reset all zoom factors to their defaults (see T able 3-10), press ZOOM ➞ Reset Zoom Factors (side). T able 3-10: Zoom Defaults Parameter Setting Zoom V ertical Position.
Appendices.
TDS 520A, 524A, 540A, & 544A User Manual 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.
Appendix A: Options and Accessories Appendices W arranty-Plus Service Options The following options add to the services available with the standard warranty . (The standard warranty appears following the title page in this manual.) Option M2: When Option M2 is ordered, T ektronix provides five years of warranty/remedial service.
Appendix A: Options and Accessories TDS 520A, 524A, 540A, & 544A User Manual Option 05: Video T rigger With this option, T ektronix ships the instrument with tools for investigating events that occur when a video signal generates a horizontal or vertical sync pulse.
Appendix A: Options and Accessories Appendices constant, or a ratio calibration technique. The calibration is in compliance with US MIL–STD–45662A.
Appendix A: Options and Accessories TDS 520A, 524A, 540A, & 544A User Manual T able A-3: Probe Accessories (Cont.) Accessory Part Number Six-inch Alligator Clip Ground Lead 196–3305–00 Screwdr.
Appendix A: Options and Accessories Appendices P6204 Active, high speed digital voltage probe. FET . DC to 1 GHz. DC offset. 50 input. Use with 1 103 T ekProbe Power Supply for offset control. P6563AS Passive, SMD probe, 20X, 500 MHz P6046 Active, differential probe, 1X/10X, DC to 100 MHz, 50 input.
Appendix A: Options and Accessories TDS 520A, 524A, 540A, & 544A User Manual T able A-5: Probe Accessories Accessory Part Number 013–0226–00 Connector , BNC: 50 , BNC to Probe T ip Adapter 013.
Appendix A: Options and Accessories Appendices Accessory Software The following optional accessories are T ektronix software products recom- mended for use with your digitizing oscilloscope: T able A-.
TDS 620A, 640A, & 644A User Manual Appendix B: Algorithms TDS 600A Digitizing Oscilloscopes can take 25 automatic measurements. By knowing how they make these calculations, you may better understand how to use your TDS 600A and how to interpret your results.
Appendix B: Algorithms Appendices 2. It splits the histogram into two sections at the halfway point between and (also called ). 3. The level with the most points in the upper histogram is the value, and the level with the most points in the lower histogram is the value.
Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual End — is the location of the end of the measurement zone (X-value). It is ( – 1.0) samples unless you are making a gated measurement. When you use gated measurements, it is the location of the right vertical cursor .
Appendix B: Algorithms Appendices MidRef + (Hysteresis x Amplitude) MidRef – (Hysteresis x Amplitude) MidRef MCross1 (StartCycle) MCross2 MCross3 (EndCycle) Figure A-1: MCross Calculations W aveform[<0.0 ... RecordLength–1.0>] — holds the acquired data.
Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual For details of the integration algorithm, see page A-19. Cycle Area Amplitude (voltage) measurement. The area over one waveform cycle. For non-cyclical data, you might prefer to use the Area measurement.
Appendix B: Algorithms Appendices For details of the integration algorithm, see page A-19. Delay T iming measurement. The amount of time between the and crossings of two different traces, or two dif ferent places on the same trace. Delay measurements are actually a group of measurements.
Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual High HighRef LowRe f Lo w TL F THF Fall Time Figure A-2: Fall Time Frequency T iming measurement. The reciprocal of the period. Measured in Hertz (Hz) where 1 Hz = 1 cycle per second. If = 0 or is otherwise bad, return an error .
Appendix B: Algorithms Appendices Maximum Amplitude (voltage) measurement. The maximum voltage. T ypically the most positive peak voltage. Examine all samples from to inclusive, and set equal to the greatest magnitude value found. Mean The arithmetic mean for one waveform.
Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual Negative Width T iming measurement. The distance (time) between (default = 50%) amplitude points of a negative pulse. If = ‘–’ then = – else = – Peak to Peak Amplitude measurement.
Appendix B: Algorithms Appendices If the target waveform leads the reference waveform, phase is positive; if it lags, negative. Phase is not available in the Snapshot display . Positive Duty Cycle T iming measurement. The ratio of the positive pulse width to the signal peri- od, expressed as a percentage.
Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual 3. From , continue the search, looking for a crossing of . Update if subsequent crossings are found. If a crossing is found, it becomes the high rise time or . (Use linear interpolation if necessary .
Appendix B: Algorithms Appendices W(t) is the sampled waveform is the continuous function obtained by linear interpolation of W(t) A and B are numbers between 0.
Appendix B: Algorithms TDS 620A, 640A, & 644A User Manual If some samples in the waveform are missing or off-scale, the measurements will linearly interpolate between known samples to make an “appropriate” guess as to the sample value.
Appendix B: Algorithms Appendices 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.
TDS 620A, 640A, & 644A User Manual Appendix C: Packaging for Shipment If you ship the digitizing oscilloscope, pack it in the original shipping carton and packing material. If the original packing material is not available, package the instrument as follows: 1.
Appendix C: Packaging for Shipment Appendices.
TDS 620A, 640A, & 644A User Manual Appendix D: Factory Initialization Settings The factory initialization settings provide you a known state for the digitizing oscilloscope.
Appendix D: Factory Initialization Settings Appendices T able A-7: Factory Initialization Defaults (Cont.) Control Changed by Factory Init to Delay trigger average # 16 Delay trigger envelope # 10 Delay time 16 ns Delay events, triggerable after main 2 Delayed, delay by .
Appendix D: Factory Initialization Settings TDS 620A, 640A, & 644A User Manual T able A-7: Factory Initialization Defaults (Cont.) Control Changed by Factory Init to Display variable persistence 500 ms Edge trigger coupling DC Edge trigger level 0.
Appendix D: Factory Initialization Settings Appendices T able A-7: Factory Initialization Defaults (Cont.) Control Changed by Factory Init to Logic state trigger Ch4 (Ax2) input Rising edge Logic trig.
Appendix D: Factory Initialization Settings TDS 620A, 640A, & 644A User Manual T able A-7: Factory Initialization Defaults (Cont.) Control Changed by Factory Init to Pulse runt high threshold 1.
Appendix D: Factory Initialization Settings Appendices T able A-7: Factory Initialization Defaults (Cont.) Control Changed by Factory Init to Zoom state Of f Zoom vertical (all channels) 1.
Glossary.
TDS 620A, 640A, & 644A User Manual Glossary AC coupling A type of signal transmission that blocks the DC component of a signal but uses the dynamic (AC) component. Useful for observing an AC signal that is normally riding on a DC signal. Accuracy The closeness of the indicated value to the true value.
Glossary Glossary Automatic trigger mode A trigger mode that causes the oscilloscope to automatically acquire if triggerable events are not detected within a specified time period. Autoset A function of the oscilloscope that automatically produces a stable waveform of usable size.
Glossary TDS 620A, 640A, & 644A User Manual Cycle RMS The true Root Mean Square voltage over one cycle. DC coupling A mode that passes both AC and DC signal components to the circuit.
Glossary Glossary Gated Measurements A feature that lets you limit automated measurements to a specified portion of the waveform. Y ou define the area of interest using the vertical cursors. General purpose knob The large front-panel knob with an indentation.
Glossary TDS 620A, 640A, & 644A User Manual Holdoff, trigger A specified amount of time after a trigger signal that elapses before the trigger circuit will accept another trigger signal.
Glossary Glossary Low The value used as 0% in automated measurements (whenever high ref, mid ref, and low ref values are needed as in fall time and rise time measurements). May be calculated using either the min/max or the histogram method. With the min/max method (most useful for general waveforms), it is the minimum value found.
Glossary TDS 620A, 640A, & 644A User Manual NOR A logic (Boolean) function in which the output of the OR function is complemented (true becomes false, and false becomes true). On the digitizing oscilloscope, that is a trigger logic pattern and state func- tion.
Glossary Glossary Positive width A timing measurement of the distance (time) between two amplitude points — rising-edge MidRef (default 50%) and falling-edge MidRef (default 50%) — on a positive pulse. Posttrigger The specified portion of the waveform record that contains data acquired after the trigger event.
Glossary TDS 620A, 640A, & 644A User Manual Sample acquisition mode The oscilloscope creates a record point by saving the first sample during each acquisition interval. That is the default mode of the acquisition. Sample interval The time interval between successive samples in a time base.
Glossary Glossary T rigger level The vertical level the trigger signal must cross to generate a trigger (on edge trigger mode). V ertical bar cursors The two vertical bars you position to measure the time parameter of a waveform record.
Index.
TDS 520A, 524A, 540A, & 544A User Manual Index Numbers 1/seconds (Hz) , Cursor menu, 3-21 100 MHz , V ertical menu, 3-149 20 MHz , V ertical menu, 3-149 A AC coupling, 2-16–2-17 , Glossary-1 AC .
Index Index DISPLA Y , 3-12 , 3-28 FORCE TRIG , 3-143 HARDCOPY , 3-55 , 3-61 , 3-128 HELP , 3-67 HORIZONT AL MENU , 2-18 , 3-23 MEASURE , 3-89 MORE , 3-134 , 3-136 , 3-159 ON/STBY , 1-4 , 2-3 Save/Rec.
Index TDS 520A, 524A, 540A, & 544A User Manual Create Limit T est T emplate , Acquire menu, 3-73 Create Measrmnt , Measure Delay menu, 3-95 Cross Hair , Display menu, 3-31 Current probes, 3-1 15 C.
Index Index Display , Display menu, 3-28 Display , Status menu, 3-140 Dots, 3-29 Dots style, Display menu, 3-75 Dots , Display menu, 3-29 DPU41 1–II , Hardcopy menu, 3-61 DPU412 , Hardcopy menu, 3-6.
Index TDS 520A, 524A, 540A, & 544A User Manual G Gated Measurements, 3-91 , Glossa- ry-4 Gating , Measure menu, 3-91 General purpose (high input resis- tance) probes, 3-1 12 General purpose knob, .
Index Index I I/O , Status menu, 3-140 I/O , Utility menu, 3-60 , 3-128 IC protector tip, 3-102 Icons, 1-1 Independent Mode, Cursor , 2-31–2-32 Independent , Cursor menu, 3-20 Infinite Persistence ,.
Index TDS 520A, 524A, 540A, & 544A User Manual T rigger When , 3-81 , 3-83 T rue for less than , 3-83 T rue for more than , 3-83 T ype , 3-34 , 3-121 , 3-123 , 3-145 Width , 3-122 MAIN TRIGGER OUT.
Index Index Set FFT V ert Scale to: , 3-40 Set FFT Window to: , 3-40 Set Function to , 3-160 Set Function to: , 3-151 , 3-155 Set operator to , 3-161 Set Single Source to , 3-160 Set Single Source to:.
Index TDS 520A, 524A, 540A, & 544A User Manual Low-inductance spring-tips, 3-101 , A-7 Marker rings, 3-100 , A-7 Probe tip-to-chassis adapter , 3-102 , A-7 Probe tip-to-circuit board adapters, 3-1.
Index Index S Safety , v Symbols, v Sample acquisition mode, 3-3 , Glos- sary-9 Sample interval, Glossary-9 Sample , Acquire menu, 3-7 Sampling, 2-20 , Glossary-9 Sampling and acquisition mode, 2-22 S.
Index TDS 520A, 524A, 540A, & 544A User Manual T ek Secure, 3-131 , Glossary-9 T ek Secure Erase Memory , Utility menu, 3-131 T emperature compensation, 3-138–3-139 T emperature , Color menu, 3-.
Index Index W W ARNING, statement in manual, v W aveform, Glossary-10 Interval, Glossary-10 Math, 3-159–3-161 Off priority , 3-137 W aveform clipping.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Tektronix 540A è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Tektronix 540A - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Tektronix 540A imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Tektronix 540A ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Tektronix 540A, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Tektronix 540A.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Tektronix 540A. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Tektronix 540A insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
