User manual

WaveSurfer 3000 Oscilloscopes
Trigger Holdoff
Holdoff is an additional condition that may be set for Edge and Pattern triggers. It can be expressed either as
a period of time or an event count. Holdoff disables the trigger temporarily, even if the trigger conditions are
met, until the holdoff conditions are also met. The trigger fires when the holdoff has elapsed.
Use holdoff to obtain a stable trigger for repetitive, composite waveforms. For example, if the number or
duration of sub-signals is known, you can disable them by choosing an appropriate holdoff value. Qualified
triggers operate using conditions similar to holdoff.
Hold Off by Time
This is a period of time to wait to fire the trigger, either since the beginning of the acquisition or since the
trigger conditions were met.
Sometimes you can achieve a stable display of complex, repetitive waveforms by placing a holdoff condition
on the time between each successive Edge trigger event. This time would otherwise be limited only by the
input signal, the coupling, and the instrument's bandwidth. Select a positive or negative slope, and a
minimum time between triggers.
In the figure below, the bold edges on the trigger source indicate that a positive slope has been selected. The
broken upward-pointing arrows indicate potential triggers, which would occur if other conditions are met. The
bold arrows indicate where the triggers actually occur when the holdoff time has been exceeded.
Edge trigger with holdoff by time.
Hold Off by Events
For purposes of Hold Off, Events refers to the number of times the trigger conditions have been met, counted
either from the beginning of the acquisition or since the last trigger. For example, if the hold-off number of
Events is 2 counted from the beginning of the acquisition, the trigger fires on the third event.
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