Tektronix TDS210 user guide: Reference

Reference

This section describes the menus and operating details associated with each front-panel menu button.

Reference

Acquire

Push the ACQUIRE button to set acquisition parameters.

Key Points

If you probe a noisy square wave signal that contains intermittent, narrow glitches, the waveform displayed will vary depending on the acquisition mode you choose.

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The next two topics describe each of the types of acquisition modes and their differences.

Sample. Use Sample acquisition mode to acquire 2,500 points and display them at the SEC/DIV setting. Sample mode is the default mode.

• Sample points Sample mode acquires a single sample point in each interval.

The maximum sample rate is 1 GS/s. At 100 ns and faster settings, this sample rate does not acquire 2,500 points. In this case, a Digital Signal Processor interpolates points between the sampled points to make a full 2,500 point waveform record.

Peak Detect. Use Peak Detect acquisition mode to detect glitches as narrow as 10 ns and to limit the possibility of aliasing. This mode is effective when at 5 µs/div or slower.

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• Sample points displayed Peak Detect mode displays highest and lowest acquired voltage in each interval.

NOTE. If you set the SEC/DIV to 2.5 \mus/div or faster, the acquisition mode changes to Sample because the sample rate is fast enough that you do not need to use Peak Detect. No message displays to tell you that the mode was changed from Peak Detect to Sample.

When there is enough waveform noise, a typical peak detect display shows large black areas. The TDS 200-series oscilloscopes displays this area with diagonal lines to improve display performance.

Typical peak detect display TDS 200 peak detect display

68 TDS 200-Series Digital Oscilloscope User Manual

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Average. Use Average acquisition mode to reduce random or uncorrelated noise in the signal you want to display. Data is acquired in sample mode, then a number of waveforms are averaged together. Select the number of acquisitions (4, 16, 64, or 128) to average for the waveform.

Scan Mode Display. When the SEC/DIV control is set to 100 ms/div or slower and the trigger mode set to Auto, the instrument enters the scan acquisition mode. In this mode, the waveform display updates from left to right. There is no horizontal position or trigger control of waveforms during scan mode.

Stopping the Acquisition. While acquisition is running, the waveform display is live. Stopping the acquisition freezes the display. In either mode, the waveform display can be scaled or positioned with the vertical and horizontal controls.

TDS 200-Series Digital Oscilloscope User Manual 69

Autose

The Autose feature automatically adjusts the controls to produce a usable display of the input signal.

Pushing AUTOSET adjusts or sets each of the following items listed.

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Cursors

Push the CURSOR button to display the measurement cursors and cursor menu.

• Only available on the TDS 224 oscilloscope.

Key Points

Cursor Movement. Use the CH 1 and CH 2 Vertical Position knobs to move cursors 1 and 2. You can move the cursors only while the Cursor menu is displayed.

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Voltage cursors Time cursors

U in Level and Delta Readouts. Vertical sensitivity should match on waveforms used for math operations. If they do not match, and you use cursors to measure the waveform result of a math operation, an U displays that represents unknown.

Display

Push the DISPLAY button to choose how waveforms are presented and to change the appearance of the entire display.

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Key Points

Persistence. When using persistence, old data retained is displayed in gray while the new data is black.

With Persistence set to Infinite, record points accumulate until a control is changed.

XY Format. This format only applies to channels 1 and 2. Choose XY display format to display channel 1 in the horizontal axis and channel 2 in the vertical axis. The oscilloscope uses the untriggered sample acquisition mode and data displays as dots. The sampling rate is 1 MS/s and can not be changed.

NOTE. The oscilloscope can capture a waveform in normal YT mode at any sampling rate. You can view the same waveform in XY mode. To do so, stop the acquisition and change the display format to XY.

The controls operate as follows:

■ The channel 1 VOLTS/DIV and vertical POSITION controls set the horizontal scale and position.

■ The channel 2 VOLTS/DIV and vertical POSITION controls continue to set vertical scale and position.

The following functions do not work in XY display format:

■ Ref or Math waveforms

■ Cursors

■ Autoset (resets display format to YT)

■ Time base controls

■ Trigger controls

Horizontal

You can use the horizontal controls to change the horizontal scale and position of waveforms. The horizontal center of the screen is the time reference for waveforms. Changing the horizontal scale causes the waveform to expand or contract around the screen center. Horizontal position changes the point, relative to the trigger, where the waveform appears on the center of the screen.

NOTE. You can push the Window menu box button to switch between an entire waveform display and an enlarged, more detailed part of it.

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Key Points

SEC/DIV. If waveform acquisition is stopped (using the RUN/STOP button), the SEC/DIV control expands or compresses the waveform.

Scan Mode Display. When the SEC/DIV control is set to 100 ms/div or slower and the trigger mode is set to Auto, the instrument enters the scan acquisition mode. In this mode, the waveform display updates from left to right. There is no trigger or horizontal control of waveforms during scan mode.

Window Zone. Use the window zone to expand a segment of a waveform to see more detail. The Window time base setting cannot be set slower than the Main time base setting.

Vertical bars define window zone

Main time base displayed

Window zone displayed

Holdoff. Use holdoff to help stabilize the display of nonperiodic waveforms.

Holdoff begins when the instrument recognizes a trigger event and disables the trigger system until acquisition is complete. The trigger system remains disabled during the holdoff time that follows each recognized trigger event.

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Math

Although you access the Math menu in the same way, the menu boxes vary, depending on the oscilloscope model, firmware version, and installed module.

Push the MATH MENU button to display the waveform math operations. Push the MATH MENU button again to turn off the math waveform display. Refer to page 89 for vertical system descriptions.

The following tables list menu boxes available based on the oscilloscope model, firmware version, and installed module.

TDS 210 and TDS 220 (Firmware V 2.00 and Above), and TDS 224 (All Versions) Oscilloscopes

• Only available on the TDS 224 oscilloscope.

NOTE. The optional TDS2MM measurement extension module adds the FFT feature to the oscilloscope. See the TDS 200–Series Extension Modules Instructions Manual.

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TDS 210 and TDS 220 Oscilloscopes (Firmware Below V 2.00) without a TDS2MM

TDS 210 and TDS 220 Oscilloscopes (Firmware Below V 2.00) with a TDS2MM

The TDS2MM Module when used with a TDS 210 or TDS 220 changes the following math operations:

■ The TDS2MM Module does not have the CH1–CH2 and CH2–CH1 math functions. To do the same functions, invert the channel you want to subtract (using the CH1 or CH2 menu) and then select the CH1+CH2 math function.

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• The TDS2MM Module moves the channel invert function from the MATH menu to the Vertical CH1 and CH2 menus.

Key Points

VOLTS/DIV. Use the VOLTS/DIV control to scale the waveforms of the channels. The math waveform is the visual sum or difference of the channel waveforms.

Channel Display for a TDS 210 or TDS 220 (Firmware Below V 2.00). Displaying a math waveform automatically removes the display of channels used to create the math waveform. Math operations are turned off if a channel used in the operation is turned on.

NOTE. You can push the menu box button of the enabled math operation on a TDS 210 or TDS 220 to switch between the math waveform and the channels used to create the math waveform.

78 TDS 200-Series Digital Oscilloscope User Manual

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Math Operations. Only one math operation is allowed. Using the subtraction selection eliminates the need to first invert and then add the waveform for subtraction operations.

Measure

Push the MEASURE button to access the automated measurement capabilities. There are five measurements available and the ability to display up to four at a time.

Press the top menu button to display the Source or the Type menu. You can choose the channel on which to take a measurement in the Source menu. You can choose the type of measurement to take (Freq, Period, Mean, Pk–Pk, Cyc RMS, and None) in the Type menu.

Source menu boxes Type menu boxes

NOTE. The optional TDS2MM measurement extension module adds the rise time, fall time, positive pulse width, and negative pulse width measurements to the oscilloscope. See the TDS 200–Series Extension Modules Instructions Manual.

TDS 200-Series Digital Oscilloscope User Manual 79

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Key Points

Taking Measurements. You can display up to four automated measurements at a time for a single waveform (or divided among the waveforms). The waveform channel must be on (displayed) to make a measurement.

Automated measurements cannot be taken on reference or math waveforms or while using XY or scan mode.

80 TDS 200-Series Digital Oscilloscope User Manual

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Save/Recall

Push the SAVE/RECALL button to save or recall instrument setups or waveforms.

Setups

Key Points

Saving and Recalling Setups. The complete setup is stored in nonvolatile memory. When you recall the setup, you will be in the mode from which the setup was saved.

When turning the instrument on, all settings return to the settings that were in place when the instrument was turned off.

Recalling the Factory (Default) Setup. You can recall the default Factory Setup to initialize the instrument to a known setup.

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Waveforms

• Only available on the TDS 224 oscilloscope.

Saving and Recalling Waveforms. For the TDS 210 and TDS 220 oscilloscopes, you can store two reference waveforms in nonvolatile memory. For the TDS 224 oscilloscope, you can store four reference waveforms, although you can only display two at a time. You can display reference waveforms simultaneously with current waveform acquisitions.

Recalled waveforms are not adjustable.

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Trigger Controls

Two types of triggering are available: Edge and Video. A different set of menus display for each trigger type.

Edge Trigger

Use Edge triggering to trigger on the edge of the input signal at the trigger threshold.

• Only available on the TDS 224 oscilloscope.

** Only available on the TDS 210 and TDS 220 oscilloscopes.

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Key Points

Normal and Auto Mode. Use Normal trigger mode to trigger only on a valid trigger. Use Auto trigger mode to let the acquisition free-run in the absence of a valid trigger. Auto allows an untriggered, scanning waveform at 100 ms/div or slower time base settings.

Single Mode. Use Single trigger mode to capture a single acquisition of an event. The content of a single acquisition sequence depends on the acquisition mode.

EXT and EXT/5 Source (TDS 210 and TDS 220 Only). The EXT trigger source uses the signal connected to the EXT TRIG connector. The EXT/5 trigger source uses the signal connected to the EXT TRIG connector and divides it by 5; this extends the trigger level range.

AC Line Source. The AC Line trigger source uses the power signal as the trigger source. Trigger coupling is set to DC and the trigger level to 0 volts.

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Coupling. Coupling allows you to filter the trigger signal used to trigger an acquisition.

■ DC passes all components of the signal.

■ AC blocks DC components and attenuates signals below 10 Hz.

■ Noise Reject passes all components of the signal but increases the peak-to-peak signal required.

■ HF Reject attenuates the high-frequency components above 80 kHz.

■ LF Reject blocks the DC component and attenuates the low-frequency components below 300 kHz.

Pretrigger. The trigger position is typically set at the horizontal center of the screen. In this case you are able to view five divisions of pretrigger information. Adjusting the Horizontal Position of the waveform allows you to see more or less pretrigger information.

Trigger View. Pushing TRIGGER VIEW displays the trigger waveform until the button is released.

When in Trigger View mode, all front-panel buttons are disabled except HARDCOPY.

TDS 200-Series Digital Oscilloscope User Manual 85

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Video Trigger

Choose video triggering to trigger on fields or the lines of an NTSC, PAL, or SECAM standard video signal.

• Only available on the TDS 224 oscilloscope. ** Only available on the TDS 210 and TDS 220 oscilloscopes.

Key Points

Sync Pulses. When you choose Normal Polarity, the trigger always occurs on negative-going sync pulses. If your video signal has positive-going sync pulses, use the Inverted Polarity selection.

Utility

Push the UTILITY button to display the utility menus. The Utility menus change with the addition of extension modules. The menus explained here relate to the product with no modules installed. Refer to the manual supplied with your extension module for items not discussed here.

TDS 200-Series Digital Oscilloscope User Manual 87

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Key Points

Self Calibration. The self calibration routine optimizes the oscilloscope accuracy for the ambient temperature. For maximum accuracy, perform a self cal if the ambient temperature changes by 5° C or more.

To compensate the signal path, disconnect any probes or cables from the input connectors. Then, select Do Self Cal to confirm that you are ready to proceed.

System Status

Selecting System Status from the utility menu displays the menus available for obtaining a list of control settings for each group of instrument controls.

Push any front-panel menu button to remove the status screen.

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Vertical

You can use the vertical controls to display waveforms, adjust vertical scale and position, and set input parameters. Refer to page 76 for the vertical math descriptions.

Channel Vertical Menus

There is a separate vertical menu for each channel. Each item is set individually for each channel.

• Bandwidth is not valid for the P2100 probe when the switch is set to 1X.

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Key Points

GND Coupling. Use GND coupling to display a zero-volt waveform. When you use GND coupling, the input BNC connector is disconnected from internal circuits. Internally, the channel input is connected to a zero-volt reference level.

Fine Resolution. The vertical scale readout displays the actual Volts/Div setting while in the fine resolution setting. Changing the setting to coarse does not change the vertical scale until the VOLTS/DIV control is adjusted.

U in Level and Delta Readouts. Vertical sensitivity should match on waveforms used for math operations. If they do not match, and you use cursors to measure the waveform result of a math operation, an U displays that represents unknown.

Waveform off. To remove a waveform from the display, push the MENU button for the channel to display its vertical menu. Push the menu button again to turn the waveform off. An input channel can still be used as a trigger source or for math displays while turned off.

Hard Copy

Push the HARDCOPY button to print a hard copy of the display. The hard-copy function requires that an extension module with a Centronics, RS-232, or GPIB port be installed and connected to a printer.

Refer to the manual supplied with your extension module for instructions on connections and using the module.

Refer to Optional Accessories on page 103 for information about the available extension modules.