Pulse Triggering
Reference
Selected Trigger Bar at Upper Threshold
Runt Pulse Crosses First Threshold
Only, Recrosses First Threshold Level,
and Triggers Acquisition
Unselected Trigger Bar at Lower
Threshold
Figure 3-63: Main Trigger Menu—Runt Class
Thresholds
To set the two threshold levels used in detecting a runt pulse:
1. Press TRIGGER MENU Type (main) Pulse (pop-up)
Class (main) Runt (pop-up) Thresholds (main).
2. Use the general purpose knob or keypad to set the values for the high
and low thresholds.
Hint: To use the Trigger Bar feature to set the threshold levels on the
pulse train, press DISPLAY Readout Options (main) Trigger Bar
Style (side) until
Long
appears in that menu item.
Note the position of the trigger indicator in Figure 3-63. Triggering occurs at
the point the pulse returns over the first (lower) threshold going negative
without crossing the second threshold level (upper). Be aware of the following
considerations when using Runt triggering:
When Positive is set in the Polarity side menu, the
lower
threshold must
be first crossed going
positive
, then recrossed going
negative
without
crossing the
upper
threshold at all.
When Negative is set in the Polarity side menu, the
upper
threshold
must be first crossed going
negative
, then recrossed going
positive
without crossing the
lower
threshold at all.
When Either is set in the Polarity side menu,
one
threshold must be first
crossed going in
either
direction, then recrossed going in the
opposite
direction without crossing the
other
threshold at all.