Tektronix 2440 digital oscilloscope

4.6.2 Waveform Call (Display REF Button)

Calling steps:

Press the PLAY REF button to enter the PLAY REF menu;

Select the reference memory to be called (REF1-REF4), and display "EMPTY" when there is no waveform;

After calling, the horizontal position of the reference waveform can be adjusted according to HORIZ POS REF;

XY mode call: Select XYREF and call the XY combination waveform from REF1-REF4.

4.7 Measurement system (waveform parameter extraction)

4.7.1 Overview of Measurement Functions

Measurement type: 17 parameters, covering amplitude, time, and special categories:

Amplitude parameters: Peak to peak value (Pk Pk), maximum value (Max), minimum value (Min), mean (Mean), RMS, overshoot (Ovrsht), undershoot (Undrsht), area (Area);

Time parameters: Period, Freq, Rise, Fall, Width, Duty, Delay;

Special parameters: Events, Slope, 1/TIME (reciprocal frequency);

Measurement methods: continuous measurement (MEAS TYPE), single snapshot (SNAPSHOT).

4.7.2 Typical Measurement Operations (Taking "Rise Time" as an Example)

Preparation work: Ensure stable signal triggering, no obvious noise on the rising edge, and horizontal time base adaptation (such as measuring ns level rise time using 5ns/div);

Enter the measurement menu: press the Measure button;

Select measurement type: Press MEAS TYPE → check "RISE" in the parameter matrix;

Set measurement standards (default 10% -90%, customization requires SETUP → LEVEL):

Rotate the knob to adjust the levels of DISTAL (corresponding to 10%) and PROXIMAL (corresponding to 90%);

Press the MARK ON button, and the screen will display measurement markers (X-shaped) indicating the 10% and 90% level positions;

Reading result: The screen measurement reading area displays the rise time value (such as 28.4ns);

Single snapshot: Press SNAPSHOT → select the target channel (such as CH1), and the instrument captures all parameters of the current waveform and freezes the display.

4.8 GPIB Communication and Data Output (OUTPUT Button)

4.8.1 GPIB parameter configuration

Enter the configuration menu: press OUTPUT → SETUP;

Core parameter settings:

Mode: T/ONLY (only sends data), L/ONLY (only receives commands), T/L (sends and receives), DEVICES (connects to printer/plotter), OFF BUS (turns off GPIB);

Address (ADDR): Set GPIB address (such as 3) to match the controller address;

Terminator (TERM): EOI (default) LF/EOI， Ensure consistency with the receiving device;

Encoding (ENCDG): ASCII, RP (positive integer), RI (default), positive integer data should be set to RP;

Device adaptation: Press DEVICES → select device type (HPGL plotter, THINKJET printer) → set paper size (US: A4), whether to display scale (GRAT ON/OFF).

4.8.2 Data Transmission and Status Monitoring

Sending data: Press the TRANSMIT/RINT button to send the current waveform (CURVE), panel settings (PRGM), or measurement results to an external device;

Status monitoring: Press OUTPUT → STATUS to check the GPIB status (such as address, mode, error messages), with the undersigned item indicating the current effective setting;

Troubleshooting: If data transmission fails, check:

Is the GPIB cable connection secure;

Whether the address, terminator, and code are consistent with the receiving device;

Does the device support the selected data format (such as WHOLE WFMS/ARTIAL WFMS).

Safe operation and precautions

5.1 Safety prerequisites

It is necessary to refer to the "Operator Safety Summary" in the 2440 Operation Manual, with a focus on:

Input voltage limit: maximum 400Vpk for 1M Ω coupling, maximum 5Vrms for 50 Ω coupling;

Probe usage: Only use Tek recommended probes (such as 10X passive probes), and the probe ground wire must not be connected to mains power;

Grounding requirements: The instrument must be grounded through a 3-pin power supply and disconnection of the grounding pin is prohibited;

Do not use in damp or explosive environments, and do not plug or unplug probes or signal cables with power on.

5.2 Maintenance and Calibration

Signal Path Compensation (SPC): If the environmental temperature difference exceeds 10 ℃ or once a week, follow Utility → Calibration → Signal Path, which takes about 10 minutes to ensure low range (≤ 5mV/div) measurement accuracy;

Probe compensation: Every time the probe or channel is replaced, a CALIBRATOR circuit needs to be connected（ 2.5V@1kHz ）Adjust the compensation hole of the probe to a straight square wave;

Calibration prompt: If the extended diagnosis displays "UNCALD", perform a SELF CAL after the instrument is preheated. If it still fails, contact a professional for calibration. At this time, the instrument may use the previous calibration parameters, and the measurement accuracy may decrease.

5.3 Common troubleshooting

Troubleshooting steps for possible causes of fault phenomena

No waveform display 1. Channel not activated; 2. The coupling method is GND; 3. Unstable triggering; 4. The brightness setting is too low. 1. Press MODE to activate the corresponding channel; 2. Switch the coupling to AC/DC; 3. Press AUTO SETUP or Initiat @ 50%; 4. Adjust the INTENSITY knob

Unstable triggering: 1. Improper triggering level; 2. The coupling method is not adapted; 3. Excessive signal noise. 1. Manually adjust TRIGGER LEVEL; 2. Enable Noise Reject coupling; 3. Switch to Average acquisition mode