Performing A Wideband Flatness Test - Fluke 5700A Series II Operator's Manual

4-69. Performing A Wideband Flatness Test

Wideband rms voltmeters such as the Fluke 8920 Series measure ac voltage into the RF
spectrum. One type of error in wideband rms voltmeters is flatness error, or error due to
uneven frequency response.
Two example procedures related to wideband flatness are given here. The first example is
a procedure to test the flatness or frequency response error of a wideband voltmeter to
within the uncertainty of the Wideband AC Module (Option 5700A-03) flatness
specification. The second example is a technique that transfers the accuracy of the
calibrator's main ac voltage output to the output of the Wideband AC Module at a low
frequency, then reads the absolute error of a meter with respect to the flatness
specification of the Wideband AC Module at a high frequency.
Example 1:
1. Connect the 3-foot cable supplied with the Wideband AC Module to the
WIDEBAND connector to the wideband voltmeter input through the supplied 50Ω
terminator.
2. Set the calibrator's wideband output to 1V at 1 kHz.
3. Adjust the wideband output with the output adjustment controls for a reading of
1.00V on the wideband voltmeter.
4. Press N to establish this as a new reference.
5. Press 1 0 m H E to set the frequency to 10 MHz.
6. Adjust the wideband output again with the output adjustment controls for a reading
of 1.00V on the wideband meter.
7. The control display now shows the frequency response error to within the uncertainty
of the Wideband AC Module flatness specification.
Front Panel Operation
Sample Applications
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