Tektronix TDS5054, Руководство пользователя

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Triggering
TDS5000 Series User Manual
3- 71
Overview Control elements and resources To trigger on a runt pulse
Select the
polarity
5. Select a Polarity value to specify the direction of the runt
pulse. 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 window determines the order
that the threshold must be crossed for a runt trigger to
occur:
H
Pos looks at positive-going pulses. The lower
threshold must be first crossed going positive, then
recrossed going negative without the upper
threshold being crossed at all.
H
Neg looks at negative-going pulses. The upper
threshold must be first crossed going negative, then
recrossed going positive without the lower
threshold being crossed at all.
H
Either looks at both positive and negative pulses.
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.
Runt pulse crosses first threshold only, recrosses first
threshold level, and triggers acquisition
Unselected trigger bar
at lower threshold.
Selected trigger bar at
upper threshold.