Pinpoint Trigge
rs
Pinpoint Triggers
The P inpoint trigger system comes with advanced trigger types that are usable on both A and B triggers, and it can reset the
trigger sequence if the B event does not occur after a specific number of events or a specific time. Pinpoint triggers support
capture of events based on the most complex trigger event or sequence of trigger events.
This section contains concepts and procedures for using the trigger system.
Triggering Concepts
Trigger Event
The trigger event establishes the time-zero point in the waveform record. All waveform record data are located in time with
respect to that point. The instrument continuously acquires and retains enough sample points to fill the pretrigger portion of
the waveform record. When a trigger event occurs, the instrument starts acquiring samples to build the posttrigger portion of
the waveform record (displayed after, or to the right of, the trigger event). Once a trigger is recognized, the instrument will not
accept another trigger until the acquisition is complete and the holdoff time has expired.
Trigger Modes
The trigger
mode determines how the i nstrument behav es in the absence of a trigger event:
Normal trig
ger mode enables the instrument to acquire a waveform only when it is triggered. If no trigger occurs, the last
waveform record acquired remains on the display. If n o last waveform exists, no waveform is displayed.
Auto trigger mode enables the instrument to acquire a w aveform even if a trigger does not occur. Auto mode uses a timer
that starts after a trigger event occurs. If another trigger event is not detected before the timer times out, the instrument
forces a tri
gger. The length of time it waits for a trigger event depends on the time base setting.
Auto mode, w
hen forcing triggers in the absence of valid triggering events, does not synchronize the waveform on the
display. The waveform will appear to roll across the screen. If valid triggers occur, the display will become stable.
You can also force the instrument to trigger with an edge trigger by clicking the Force Trigger button on the Trigger Setup
control window.
Select the trigger mode in the Trig > Mode menu. For more information, see the instrument online help.
Trigger Ho
ldoff
Trigger holdoff can help stabilize triggering. When the instrument recognizes a trigger event, it disables the trigger system
until acquisition is complete. In addition, the trigger system remains disabled during the holdoff period that follows each
acquisition. Adjust holdoff to obtain stable triggering w hen the instrument is triggering on undesired trigger events.
Set the trigger holdoff in the Trig > Holdoff menu. For more information, see the instrument online help.
26 DPO7000 Series Q uick Start User Manual
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