Tektronix Trigger Coupling

Triggering
3-76 CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments User Manual
CSA7404, CSA7154, TDS7404, TDS7254, TDS7154, TDS6000 Series:
Random holdoff selects a new random holdoff time for each acquisition cycle.
Random holdoff is only available when A only, Edge triggering is selected.
Rather than helping the instrument synchronize on a particular feature of a pulse
train, random holdoff prevents synchronization, helping to reveal features of
some pulse trains.
Indicates trigger points
Trigger level
At the longer holdoff time for the top waveform, unstable triggering occurs. With a shorter holdoff set for
the bottom waveform, triggers all occur on the first pulse in the burst to remedy the unstable trigger.
Holdoff Holdoff Holdoff
Trigger level
Holdoff Holdoff Holdoff Holdoff
Figure 3- 23: Holdoff adjustment can prevent false triggers
Trigger coupling determines what part of the signal is passed to the trigger
circuit. Edge triggering can use all available coupling types: AC, DC, Low
Frequency Rejection, High Frequency Rejection, and Noise Rejection. All the
advanced trigger types use only DC coupling. See To set the trigger coupling on
page 3--81 for a description of each coupling type.
Trigger Coupling