BK Precision 2560B Series, Руководство пользователя

Страница: 73 / 224

Trigger
73
9.6 Trigger Holdoff
Trigger holdoff can be used to add an additional, user-defined delay to the re-arming of the trigger circuit. This provides
control over how rapidly, or how often, the oscilloscope can be triggered. The oscilloscope will not trigger until the
holdoff time expires.
Use the holdoff to trigger on repetitive waveforms that have multiple edges (or other events) between waveform repetitions.
You can also use holdoff to trigger on the first edge of a burst when you know the minimum time between bursts.
9.6.1 Holdoff by Time
Holdoff time is the amount of time that the oscilloscope waits before rearming the trigger circuitry. The oscilloscope will
not trigger until the holdoff time expires.
Use the holdoff to trigger on repetitive waveforms that have multiple edges (or other events) between waveform repetitions.
You can also use holdoff to trigger on the first edge of a burst when you know the minimum time between bursts.
For example, to achieve a stable trigger on the repetitive pulses shown in the figure below set the holdoff time (t) to 200
ns < t < 400 ns.
Figure 9.26 Holdoff
9.6.2 Holdoff by Event
The holdoff event is the number of events that the oscilloscope counts before re-arming the trigger circuitry. The
oscilloscope will not trigger until the counter tracking holdoff events reaches the set value.
Finding the Repetition of a Waveform
To find the repetition of the waveform:
1. Press the Stop key to stop data acquisition.
2. Turn the Horizontal Position Knob and the Horizontal Scale Knob to find where the waveform repeats.
3. Measure the time using the cursors function.
4. Set the Holdoff time.