Technical data

Advanced Triggering, Search & Navigation, and Segmented Acquisition Labs 3
4000 X-Series Oscilloscopes Advanced Training Guide 47
You should now see on your scope’s display a digital burst waveform
consisting of six pulses of various widths, followed by an infrequent glitch
similar to Figure 25. Using the scope’s default Edge triggering mode, the
scope usually triggers on the 1st pulse of this burst. But if you increase
the scope’s waveform intensity to 100%, you will see that the scope
sometimes triggers on later pulses within this burst. We could further
stabilize triggering on the 1st pulse in this burst if we used the scope’s
trigger holdoff capability. But what if we wanted to trigger on a specific
pulse (other than the 1st pulse)? We could accomplish this by using the
“Nth Edge Burst” triggering mode, assuming that the input signal is a
repetitive burst. We will show how to use the “Nth Edge Burst” triggering
mode in the next lab (Lab #9). Another option would be to use the scope’s
“Pulse Width” triggering mode, which can be used on a continuous data
stream of digital pulses; the data stream does not need to come in bursts.
But the pulses must have a unique pulse width for this triggering mode to
be effective. Note that the 5th pulse within this burst has a positive pulse
width of approximately 300 ns. This is a unique pulse width within this
burst of pulses. Let’s now set up the scope to trigger specifically on this
pulse.
9 Press the [Trigger] front panel key; then tap the Pulse Width trigger type
from the Trigger Type menu.
10 Tap the “ < > >< ” softkey until the “><” time qualifier has a check
below it.
11 Tap the “ < 30 ns ” softkey; then set the time to < 350 ns using the
keypad.
12 Tap the “ > 20 ns ” softkey; then set the time to > 250 ns using the
keypad.
13 Set the scope’s timebase to 500.0 ns/div.