LeCroy HFP1500 Instruction Manual page 36

HFP1500 High Frequency Probe
8. Add 10 (to correct for the +10 V offset as described in step B-13) to the 'PS Negative
Output Voltage' recorded in step B-7. (Do NOT adjust the power supply output amplitude).
9. Divide the resulting sum by 10.
10. Record the answer to three significant places as 'Expected Negative Output Voltage" in
the test record.
11. Remove the banana plug adapter, connected to the power supply, from the DMM and con-
nect the precision 50 Ω terminator to the DMM, making sure that the banana plug side
marked 'GROUND" is connected to the LOW or COMMON input of the DMM.
12. Set the DMM to read DC Volt on the most sensitive range.
13. Verify that the display for channel 1 is turned ON. Turn the oscilloscope OFFSET knob to
read +10.00 V on the oscilloscope display.
14. After the DMM has settled, record the reading to 100 µV resolution as 'Measured Negative
Output Voltage' in the Test Record.
15. Subtract the measured voltage as recorded in step B-14 from the expected output voltage
recorded in step B-10. Be sure to include the sign of each of the values in the calculation.
16. Record the answer to three significant places as 'Offset Error Voltage' in the Test Record.
17. Verify that the error is between ±10.8 mV.
The error term is derived from the Offset Accuracy specification of ±1% ±8 mV.
Using a 10.0 V offset setting, the maximum error would be 108 mV referred to the
input, which becomes ±10.8 mV error referred to the output (taking into account
÷
the 10 attenuation).
18. Using the oscilloscope's OFFSET knob, set the probe offset to 0 V, as indicated in the on-
screen display.
19. Remove the dual banana plug adapter with the HFP1500 attached from the power supply
and reconnect to the supply but now with the grounded side of the banana plug (and
grounded socket of the probe head) connected to the negative terminal of the power sup-
ply output.
20. Disconnect the DMM from the precision 50 Ω terminator and connect the DMM to the dual
banana plug adapter connected to the power supply output.
21. Record the DMM reading, which should be a positive number, to 10 mV resolution as
'Power Supply Positive Output Voltage' in the Test Record.
22. Subtract 10 from the output voltage recorded in step B-21. Divide this number by 10.
23. Record the result to three significant places as 'Expected Positive Output Voltage' in the
Test Record.
24. Set the oscilloscope OFFSET to –10.00 V as read on the oscilloscope display.
7–6
Note:
HFP1500-OM-E Rev E