Tektronix TLS 216 User Manual page 223

Triggering on Pulses
To Understand Pulse Triggers
Classes of Pulse Triggers
The Pulse
Triggering Process
TLS 216 User Manual
The TLS 216 Logic Scope can trigger on glitches or pulses based on their width.
It compares the trigger source input with the glitch or pulse width limit (or
range) you specify and triggers when the comparison meets your specification.
This article describes how to select glitch or pulse triggering and how to time
qualify the glitch or pulse width to trigger on. Setting up for pulse triggering
using the delayed trigger system is identical except where noted. Refer to
Triggering After Delay, on page 3–121, to learn about using the delayed trigger
system.
To discover how Pulse triggering occurs, read the following topics.
There are two classes of pulse triggering — glitch and width.
A glitch trigger occurs when the trigger source detects a pulse narrower or,
optionally, wider than some specified time. The logic scope can trigger on
positive or negative glitches.
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 logic scope can trigger on positive or negative pulses.
To effectively use the pulse triggering, consider the process used by the logic
scope trigger on a pulse.
1. After holdoff ends, the logic scope monitors the input you select as the
trigger source for threshold crossings that define a pulse (and its width) of
the polarity you select.
2. As the logic scope locates pulses, it compares their width with the time
qualification you set in the Trig When menu.
3. If the pulse width satisfies the time qualification, the logic scope triggers.
Table 3–8 lists the four definitions available for pulse triggering.
3–141