Triggering
3-46 CSA8000B & TDS8000B User Manual
recognize when the next trigger conditions are satisfied and cannot generate the
next trigger event. When instrument is triggering on undesired events
(Figure 3--14, top waveform), you adjust holdoff to obtain stable triggering.
Indicates trigger points
Trigger level
At the longer holdoff time for the top waveform, triggering occurs at valid, but undesired, trigger
events. With a shorter holdoff set for the bottom waveform, triggers all occur on the first pulse in the
burst, which results in a stable display.
Holdoff Holdoff Holdoff
Trigger level
Holdoff Holdoff Holdoff Holdoff
Figure 3- 14: Holdoff adjustment can prevent false triggers
Usable Holdoff. The holdoff time the instrument can use varies within limits. The
maximum holdoff the instrument can achieve is the 50 ms specified in Specifica-
tion on page Table A--3 on page A--3.
The minimum holdoff used depends on hardware constraints, which do not
change, and certain control settings, which you can control:
HThe instrument hardware constrains the minimum usable holdoff time to the
greater of the trigger-to-end-of-record time or 5 s.
HThe trigger-to-end-of-record time (EORT) is the time from the trigger event
to the last sample in the waveform record and is calculated as:
EORT = Horiz. Position + (1 -- 0.01 x Horiz. Ref.) x Time/Div x 10
divisions) + Channel Deskew