Triggering on Waveforms
TDS 500C, TDS 600B, & TDS 700C User Manual
3–95
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 3–47: Main Trigger Menu — Runt Class
Note the position of the trigger indicator in Figure 3–47. Triggering occurs at the
point the pulse returns over the first (lower) threshold going negative without
crossing the second threshold level (upper). The polarity selected in the Polarity
side menu determines the order that the threshold must be crossed for a runt
trigger to occur:
Positive requires that the lower threshold must be first crossed going positive,
then recrossed going negative without the upper threshold being crossed at all.
Negative requires that the upper threshold must be first crossed going negative,
then recrossed going positive without the lower threshold being crossed at all.
Either requires only that either one of the thresholds must be first crossed going
in either direction, then recrossed going in the opposite direction without the
other threshold being crossed at all.
For all three polarity settings, triggering occurs at the point the runt pulse
recrosses its first threshold.