HP 54710A User's Reference Manual page 351

Limit Test Menu
Run Until
Failures Failures runs the limit test until a set number of failures
occurs. When failures is selected, another softkey is displayed that
allows you to set the number of failures.
Use the failures mode when you want the limit test to reach completion after
a set number of failures. The total number of failures is additive for all of the
measurements. For example, if you select 10 failures, the total of 10 failures
can come from several measurements. The 10 failures can be the sum of
four rise time failures, four + width failures, and two Overshoot failures.
Waveforms Waveforms runs the limit test until a set number of
waveforms are acquired. When waveforms is selected, another softkey is
displayed that allows you to set the number of waveforms from 1 to 1
billion.
In the real-time acquisition mode, a waveform is acquired with each trigger
event. That is because 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 limit test operates in conjunction with the
completion softkey in the acquisition menu. If the Completion softkey is set
to off, measurements and limit test consider each trigger event as a
waveform. Older data from previous triggers is still retained in memory and
the latest trigger may or may not add additional data points to the waveform.
When Completion is on, Completion acts like a holdoff control because the
measurement is held off until after the Completion criteria is met. If limit
test is on, it also waits for a measurement before testing the measurement
results. For example, if Completion is set to 95%, then measurements are
performed on the data after 95% of the waveform record is filled with data.
Depending on the setup of the oscilloscope, it can take several triggers before
the Completion criteria is met. After the Completion criteria is met,
measurements are performed and limit test checks the measurement results.
The data is then cleared from memory, and the oscilloscope starts acquiring
new data.
Use the waveforms mode when you want the limit test to reach completion
after a set number of waveforms are acquired. The test terminates with the
measurement that first reaches the specified number of waveforms.
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