Triggering on Waveforms
TDS 500C, TDS 600B, & TDS 700C User Manual 3–67
Holdoff Holdoff
Indicates
Trigger Points
Trigger Level
Holdoff
Acquisition
Interval Acquisition
Interval
Triggers are not recognized during holdoff time.
Figure 3–33: Trigger Holdoff Time Ensures Valid Triggering
Trigger coupling determines what part of the signal is passed to the trigger
circuit. All trigger types except edge triggering use only DC coupling; edge
triggering can use all available coupling types: AC, DC, Low Frequency
Rejection, High Frequency Rejection, and Noise Rejection: See To Specify
Coupling on page 3–74 for a description of each coupling mode.
The adjustable feature trigger position defines where on the waveform record the
trigger occurs. It lets you properly align and measure data within records. The
part of the record that occurs before the trigger is the pretrigger portion. The part
that occurs after the trigger is the posttrigger portion.
To help you visualize the trigger position setting, the top part of the display has
an icon indicating where the trigger occurs in the waveform record. You select in
the Horizontal menu what percentage of the waveform record will contain
pretrigger information.
Displaying pretrigger information can be valuable when troubleshooting. For
example, if you are trying to find the cause of an unwanted glitch in your test
circuit, it might trigger on the glitch and make the pretrigger period large enough
to capture data before the glitch. By analyzing what happened before the glitch,
you may uncover clues about its source.
Trigger CouplingTrigger Position