Keysight 4000 X-Series, Руководство по продвинутой подготовке

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Advanced Triggering, Search & Navigation, and Segmented Acquisition Labs
3
4000 X-Series Oscilloscopes Advanced Training Guide 45
You should see on your scope’s display what may appear to be an un-triggered
display of a series of digital pulses similar to Figure 22 . The scope is actually
triggering on random rising edge crossings of this complex digital data stream,
which is actually a “burst” of pulses. Unfortunately we can’t “see” the burst activity
because we haven’t yet set up the scope to establish a unique trigger point on this
complex signal. So let’s now “stop” repetitive acquisitions so that we can see a
single-shot acquisition of the bursts, and then make some measurements. We will
then use these measurements to enter a specific trigger holdoff time in order to
synchronize triggering on the 1st pulse of each burst.
9
Press the
[Run/Stop]
front panel key to stop repetitive acquisitions.
With repetitive acquisitions stopped, you should now be able to see digital burst
activity as shown in Figure 23 . In other words, there are a series of negative pulses
followed by a short idle-time (high level), and then it repeats. If you press
[Single]
several times, you should observe that the trigger event (rising edge closest to
center-screen) for each acquisition is almost always a different pulse within the
burst.
Figure 23 Single-shot acquisition reveals digital burst activity.