58452 VXIbus Universal Power Meter
4-12 Publication 21555, Rev. E, September 2002
Power readings are determined using the thermistor power meter in the same general way as given in the
Power Reference Level test. That is, P1 and P2 in the Power Meter reading column of the Performance
Verification Test Data Sheet tables are calculated each time for the respective values of V
COMP
, V
0
, and
V
1
as read on the DVM.
3. To ensure accurate and repeatable measurements, the HP 432A power meter should be zeroed just
before taking each reading that will be used to calculate P1 in the Power Meter column of the
Performance Verification Test Data Sheet.
4.4.2.3 Test Procedure
1. Set the step attenuator to 70dB. Turn the source power output off, and then zero the power meter
(the power meter is zeroed by sending
CAL1:ZERO)
2. Set the step attenuator to 0dB after the power meter has zeroed.
3. Set the power output of the RF source so that the thermistor power meter indicates
1.00mW
±0.025mW.
4. Record the calculated power meter reading and the power meter reading at the end of this chapter.
The power meter data is obtained by sending
MEAS1? (or MEAS2?) and then receive the data.
5. Set the power output of the RF source so that the thermistor power meter indicates
3.98mW
±0.10mW.
6. Record the new calculated power meter reading and the new power meter reading in the correct
columns of the Linearity Data section of the data sheet.
7. Set the power output of the RF Source so that the thermistor power meter indicates
3.98mW
±0.10mW.
8. Record the calculated power meter reading and the power meter reading in the correct columns of
the Linearity Data section of the data sheet.
9. Set the power output of the RF Source so that the thermistor power meter indicates
5.01mW
±0.13mW.
10. Record the new calculated power meter reading and the new power meter reading in the correct
columns of the Linearity Data section of the data sheet.
11. Repeat using the power meter indications in the Test Data sheet. Note that the Step Attenuator
generates the remaining 70dB range of 10dB steps for a total range of 80dB. Repeat Step1
between each 10dB step shown on the Linearity Data section of the data sheet.
12. Make the calculations indicated on the Linearity Data section of the test data sheet and enter the
values in the appropriate blank spaces.
This completes the performance tests for the power meter and its sensors. If the meter has performed as
described in this chapter, it is correctly calibrated and within specifications.
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