To Trigger On A Complex Waveform - HP 54600A User's And Service Manual

Operating Your Oscilloscope
To trigger
01
a co11plex wavefor•
To trigger on a complex waveform
The difficulty in viewing a complex waveform is triggering on the signal.
Figure 6 shows a complex waveform that is not synchronized with the
trigger.
The simplest trigger method is to trigger the oscilloscope on a sync pulse
that is associated with the waveform. See "To trigger the oscilloscope"
on page 16. If there is no sync pulse, use the following procedure to
trigger on a periodic complex waveform.
1 Connect a signal to the oscilloscope.
2 Set the trigger level to the middle of the waveform.
3 Adjust the Holdoff knob to synchronize the trigger of the
oscilloscope with the complex waveform.
By setting the Holdoff to synchronize the trigger, the oscilloscope
ignores the trigger that results in figure 6, and waits for the trigger that
results
in
figure 7. Also notice
in
figure 6 that the trigger is stable, but
the waveform is not synchronized with the trigger.
Holdoff operatllg •lat
The advantage of digital holdotf is that it is a fixed number. As a result, changing
the time base settings does not affect the holdotf number; so, the oscilloscope
remains triggered. In contrast, the holdoff in analog oscilloscopes is a function of
the time base setting making it necessary to readjust the holdoff each time you
change the time base setting.
30
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