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Test Descriptions
Gain Measurement Uncertainty
Gain Measurement Uncertainty
NOTE
You must perform the Noise Figure Range and Accuracy performance test (see
page 55) before this test.
Test Description
The NFA uses internal IF attenuator values for measuring gain. The test comprises
of an internal IF attenuator calibration. Using an external 50 MHz CW signal at
-46dBm the attenuator values are computed as error ratios.
The analyzer only uses a range of 40dB for any given measurement from -20dB to
>+40dB within the available 0 - 70dB IF attenuator range. Therefore, the actual
Instrumentation Uncertainty is calculated as the maximum peak to peak error over
any 40dB range within the available 0 - 70dB IF attenuator range. The 30 available
ranges are all tested for the maximum and minimum Peak to Peak values within
their respective 40dB range. The 30 peak to peak values are then compared and the
worst case error is reported as the Instrumentation Uncertainty error.
The graph below shows a typical plot of the data. 1 of the 30 available ranges is
shown giving the typical Instrumentation Uncertainty for the specific range between
30 to 70dB.
Chapter 2
63
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