HP 8568B 16.Residual FM Test

16.Residual FM Test

Specification <3 Hz peak-to-peak in 110 s; frequency span ~100 kHz, resolution bandwidth 530 Hz, video bandwidth 530 Hz.

Description The spectrum analyzer CAL OUTPUT is used to supply a stable 20 MHz signal to the analyzer. The analyzer is tuned in zero span to a point on the 30 Hz bandwidth response for which the slope of the response is known from direct measurement. The residual FM is then slope detected over a 10 second interval, yielding a trace whose peak-to-peak excursion is proportional to the residual FM.

Equipment None Required

Procedure 1. Press (~N~TR PRESET).

2.Connect CAL OUTPUT to SIGNAL INPUT 2.

3.Press (RECALL) 8 and adjust AMPTD CAL for a MARKER amplitude of -10.00 dBm ho.02 dB.

4.Press CRECALL) 9 and adjust FREQ ZERO for a maximum amplitude trace.

5.Set PREFERENCE LEVEL) to -10 dBm. Adjust FREQ ZERO counterclockwise until trace is at the center graticule line.

6.Set ~FREQUENCY SPAN) to 100 Hz. Press SWEEP CSINGLE) and wait for completion of the sweep.

7.Press MARKER Cm), and place marker 1 division above the center graticule line on the negative-going side of the trace. Press MARKER In] and set the movable marker 1 division below the center graticule line. See Figure 2-28.

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