Teledyne LeCroy AP034 User Manual

Page 48

AP034 Active Differential Probe

922261-00 Rev A

5. Connect the other end of the cable to the DMM input, making sure that the plug

corresponding to the BNC shield (marked “Ground”) is connected to the LO or COM input.

6. Set the DC Voltage Source to read as close as possible to +1.600 V on the DMM.

7. Autobalance the AP034 by pressing the AUTOBALANCE menu button located in the

“COUPLING” menu twice, or by pressing and holding both probe offset buttons for at least
two seconds.

8. Disconnect the BNC cable from the female BNC-to-dual male banana plug adapter on the

DMM.

9. Reconnect the BNC cable from the DC Voltage Source to the Differential Drive No

Termination connector on the AP033/AP034 Calibration Fixture.

10. Set the probe offset to –1.600 V by rotating the OFFSET knob in the channel section of the

oscilloscope.

11. Allow 10 seconds for the AP034 to stabilize.

12. Using a low capacitance screwdriver, adjust Offset (R330) to bring the trace back to exactly

center screen. (See Figure 9 for adjustment location.)

13. Remove the dual banana plug adapter from the output of the DC voltage source and

reconnect it, with the pins reversed. (The plug corresponding to the BNC shield (marked
“Ground”) should now be connected to the +Output connector.)

14. In the CHANNEL menu of the oscilloscope, set the probe offset to +1.600 V by rotating the

OFFSET knob.

15. Allow 10 seconds for the AP034 to stabilize.

16. Note the amplitude of the trace from center screen.

17. Adjust Offset Cal (R330) to position the trace to approximately ½ the amplitude from

center screen noted in the previous step. This amplitude should be within •}10 mV of
center screen. Note this value.

18. Again, remove the dual banana plug adapter from the output of the DC voltage source and

reconnect it, with the pins reversed. The plug corresponding to the BNC shield (marked
“Ground”) should now be connected to the – or Common Output connector.

19. In the CHANNEL menu of the oscilloscope, set the probe offset to –1.600 V by rotating the

OFFSET knob.

20. Allow 10 seconds for the AP034 to stabilize.