Tektronix TLS 216 User Manual page 209

Triggering on Edges
To Understand Edge Triggering
To Check Trigger Status
TLS 216 User Manual
The TLS 216 Logic Scope can trigger on the rising or falling edge of a wave-
form. The logic scope monitors the amplitude level of the trigger source you
specify, and when the level passes through the threshold level you set, it triggers.
This article describes how to set the edge source, slope, threshold level, and
mode (auto or normal) in the main trigger system. Setting up for edge 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 understand edge triggering, consider the process used by the logic scope to
trigger on a waveform edge (edges are rising or falling transitions):
1. After hold off ends, the logic scope continuously monitors the instantaneous
amplitude of the input you select as a trigger source: Ch 1 through Ch 16,
the Auxiliary Trigger input, or the AC Line frequency.
2. The logic scope compares this amplitude with the threshold level you set for
triggering.
3. If the trigger source amplitude transitions through the threshold level and the
transition is in the direction you specify for edge slope (rising or falling
edge), the logic scope triggers at the point it crosses the threshold.
Since edge type triggers on waveform transitions, you can trigger on almost any
type of signal. Use edge triggering as your general-purpose trigger.
To tell if the currently selected trigger type is edge, check the trigger readout
displayed in the lower right corner of the display.
To quickly check the threshold level relative to the waveform display, check the
trigger bar indicator at the right edge of the display.
To quickly check the currently defined source, slope, and threshold level, push
TRIGGER MENU Edge (pop-up). (See Figure 3-61 on page 3–129.)
To determine the overall setup for the edge trigger, press SHIFT
Trigger (main). Select from the Thresholds, Main, and Delay (side) status
selections. (See Figure 3-60.)
STATUS
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