TDS 620A, 640A, & 644A User Manual
Pulse Triggering
Pulse triggering can be very useful. For example, you might be testing a
product with a glitch in the power supply. The glitch appears once a day. So
instead of sitting by and waiting for it to appear, you can use pulse triggering
to automatically capture your data.
There are three classes of pulse triggering: glitch, runt, and width.
A

glitch

trigger occurs when the trigger source detects a pulse narrower
(or wider) in width than some specified time. It can trigger on glitches of
either polarity. Or you can set the glitch trigger to reject glitches of either
polarity.
A

runt

trigger occurs when the trigger source detects a short pulse that
crosses one threshold but fails to cross a second threshold before re-
crossing the first. You can set the oscilloscope to detect positive or nega-
tive runt pulses.
A

width

trigger occurs when the trigger source detects a pulse that is
inside or, optionally, outside some specified time range (defined by the
upper limit and lower limit). The oscilloscope can trigger on positive or
negative width pulses.
Figure 3-61 shows the pulse trigger readouts. Table 3-9, on page 3-120,
describes the choices for pulse triggers.
Trigger Class = Runt
Figure 3-61: Pulse Trigger Readouts