Teledyne LeCroy AP034 - Manual (Page 50)

AP034 Active Differential Probe
44 922261-00 Rev A
F. Adjust Final Attenuator Compensation (C17)
NOTE: The calibrator signal from a Teledyne LeCroy oscilloscope is the recommended signal source
for this adjustment. If another oscilloscope is being used for this procedure, make sure that the
square wave source has adequate flatness (minimum overshoot and undershoot.)
1. Press the U
TILITIES
button, then select the CAL BNC Setup menu. Set the mode to CAL signal,
Shape to Square, Amplitude to 1 V into 1 MΩ, and Frequency to 1 kHz.
2. Reconnect the free end of the ProBus Extender BNC cable to the oscilloscope end of the
extender located on channel 1.
3. Connect a BNC cable from the CAL output BNC connector to the Differential Drive 50 ohm
Termination connector on the AP033/AP034 Calibration Fixture.
4. Carefully connect the Differntial Drive 50 ohm Termination portion of the AP033/AP034
Calibration Fixture to the probe tip. Press the probe into the fixture to fully engage the
pins.
5. Set the oscilloscope display to channel 1, vertical scale factor to 50 mV/div and the
horizontal scale to 1 µs/div. Set the trigger source to channel 1, and Slope to Positive.
Adjust the oscilloscope trigger level as necessary for a stable display.
6. Using the OFFSET control, move the trace down until the top portion of the waveform is
centered.
7. Using the 0.25 in. square adjustment tool, adjust Attenuator Comp (C17A) for a flat top
waveform. (See Figure 11 for adjustment location.)
8. Remove the cable from the CAL output connector on the scope.
G. Adjust Final Attenuator CMRR (C18A)
1. Carefully move the AP033 probe head from the Differential Drive 50 ohm Termination
portion of the AP033/AP034 Calibration Fixture to the Common Mode Drive 50 ohm
Termination portion.
2. Remove the BNC cable from the Differential Drive 50 ohm Termination connector of the
AP033/AP034 Calibration Fixture. Connect one end of the BNC cable to the Common Mode
Drive 50 ohm Termination connector of the AP033/AP034 Calibration fixture. Connect the
other end of the cable to the female end of a BNC Tee adapter. Plug the male connector of
the BNC Tee adapter into the channel 4 input of the oscilloscope. Connect a second BNC
cable to the remaining female connector of the BNC Tee adapter. Connect the other end of
the second BNC cable to the CAL output BNC connector.