AM-48 Test Set (18-0015) Measurements
0015-S08
-11
See the tables in Figure 7-6 for information on the ranges of the
parameters. A typical duration time for the study is 15 minutes,
although a study of up to 33 hours could be made. Note that only
values for the low level and the delta are set, which determines all
three (3) levels.
8.10 Phase Jitter
This measurement requires a 1004 Hz nominal Holding Tone. This
test measures the peak-to-peak phase variation of the modulation of
the holding tone. The bandpass (range of frequencies) is selected,
over which the phase jitter is to be measured. A phase-locked-loop
generator locks on to the Holding Tone and an average peak-to-peak
phase jitter is measured in degrees.
The bandpass (bandwidth) can be set to either:
• 4 Hz to 300 Hz or
• 20 Hz to 300 Hz
The exact frequency of the Holding Tone is known because it is the
same as the displayed phase-locked-loop frequency.
8.11 Amplitude Jitter
The test setup for amplitude jitter is the same as the phase jitter
measurement (¶8.10) except that instead of measuring the variation of
the phase, the variation of the amplitude of the modulation is
measured. The unit of measurement for the amplitude jitter is
average percent peak-to-peak variation.
Since this is an amplitude measurement, the phase-locked-loop
frequency is not of interest.
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