artisan 8640B - AM Sensitivity and Accuracy Test Setup

Model 8640B TM 9-4935-601-14-7&P
PERFORMANCE TESTS
4-34. AM SENSITIVITY AND ACCURACY TEST (Cont'd)
DESCRIPTION:
AM sensitivity accuracy and meter accuracy are measured by comparing the actual amount of amplitude modulation to
the level of the input modulating signal. A spectrum analyzer is used to demodulate the AM. The analyzer is used with
zero frequency span at the carrier frequency. A DVM is used to measure the ac and dc voltages at the analyzer's vertical
output, and the dc value of the carrier is set to 282.8 mVdc; the rms value of the modulation is then a very accurate
measure of AM percent (% AM is 1/2 the ac voltage in mVrms).
Figure 4-20. AM Sensitivity and Accuracy Test Setup.
EQUIPMENT:
Spectrum Analyzer...........................................................HP 141T/8552B/8554B
Digital Voltmeter .......................................................................HP 3480B/3484A
Test Oscillator........................................................................................HP 652A
Calibrated Step Attenuator.....................................................HP 355D OPT H36
PROCEDURE:
1. Connect equipment as shown in Figure 4-20 after setting Signal Generator's controls as follows:
Meter Function................................................................................................AM
COUNTER MODE: EXPAND ..........................................................................Off
LOCK ..............................................................................Off
Source ........................................................................... INT
AM.................................................................................................................A C
MODULATION..........................................................................................Full cw
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