TB 9-6625-2171-24
(3) Center sinewave on oscilloscope crt and adjust trigger level control to start
sinewave at horizontal graticule centerline.
(4) Utilizing a delay time of 10 Ps/div, expand the fifth cycle portion of the TI signal
as indicated in figure 5. Measure and verify the width of the jitter. Verify the deviation of
the expanded jitter display, as shown in figure 6, is equal to 48.5 Ps +3 Ps.
NOTE
The width of the jitter is proportional to the 9960 Hz FM
signal. A 9960 Hz signal deviating r480 Hz varies between
9480 and 10,440 Hz. The period of 10,440 Hz is 95.785 Ps and
the time for five cycles is 478.925 Ps. The period of 9480 Hz is
105.485 Ps and the time for five cycles is 527.425 Ps. The
difference between them (527.425 Ps minus 478.925 Ps) is 48.5
Ps. For a tolerance of 480 30 Hz deviation, the width of the
jitter must be 48.5 3 Ps.
Figure 5. 9960 Hz FM deviation display.
14