D
Measurement Uncertainty Analysis - Instrument Accuracy Test
D-150
E4416A/E4417A Power Meters Service Guide
Measurement Introduction
In the Instrument Accuracy test the DUT measures power levels output from
the test station from
−
25 dBm to +20 dBm.
A modified 8482A sensor is used to perform this measurement; it has had its
thermocouple sensor (RF to DC converter) removed. This allows extremely
accurate DC levels to be injected into the sensor from a 3245 Universal Source.
The output from the universal source is measured at the head of the sensor by
a 3458 DMM. In effect there is now zero measurement uncertainty associated
with the Universal Source, as the 3458 DMM has assumed all the uncertainty.
In this test, DC signals are injected into the modified sensor. These are made
in 5 dB steps, from
−
25 dBm to +20 dBm. A conversion from voltage to power is
required to achieve this. The measurement setup is shown in
Figure D- 1
.
Figure D-1
Measurement Setup
DVM
Universal Source
DUT
8482
Power Meter
T-Piece to measure
DC Drive Accurately
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