HP 54710A User's Reference Manual page 376

Mask Menu
Run Until
In the real-time acquisition mode, a waveform is acquired with each trigger
event. In the real-time acquisition mode, all the data points that make up a
waveform are acquired from a single trigger event. If you select 10
waveforms, that is the same as 10 trigger events.
In the equivalent-time sampling mode, a waveform is reconstructed from
several trigger events. The mask test operates in conjunction with the
completion softkey in the acquisition menu. If the Completion softkey is set
to off, mask test considers each trigger event as a waveform. Older data
increments the counters on each trigger event. For example, older data may
have incremented some of the counters to a thousand.
When Completion is on, Completion acts like a holdoff control because the
test is held off until after the completion criteria is met. For example, if
completion is set to 95%, then the counters are incremented after 95% of the
waveform record is filled with data. The counters will have a lower count
than if completion was turned off. Depending on the setup of the
oscilloscope, it can take several triggers before the Completion criteria is met.
Samples Samples runs the mask test until a set number of samples are
acquired. When samples is selected, another softkey is displayed that
allows you to set the number of samples.
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