HP 54620A, Руководство пользователя и сервисное руководство

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Some measurements you want to make will require you to take some action
in the circuit under test to cause the trigger event. Usually, these are
single-shot acquisitions, where you will use the Single key. If you use Normal
mode and wait for the trigger condition indicator to flash before causing the
action in the circuit, the analyzer will always find the trigger condition
correctly.
The Memory bar at the bottom of the waveform display shows the part of
acquisition memory that is displayed, and that which is off-screen. The
following figure shows how to interpret the Memory bar.
Memory Bar
Trigger Functions
Both the minimum detectable pattern width and the minimum duration
trigger setting depend on the current sample period. These are two different
things. The minimum detectable pattern width defines the minimum time for
which the input must remain stable so that the analyzer can recognize it as
matching a pattern trigger specification. The minimum duration trigger
setting specifies the shortest duration value that the analyzer can use.
At very fast sweep speeds (small Time/Div settings), the minimum detectable
pattern width is nearly a constant value. At Time/Div settings 2
µ
s/div and
slower, the minimum detectable pattern width is approximately a constant
value plus one sample period.
The dots show that part
of acquisition memory is
off-screen; you can view
this by panning with the
Delay knob.
The solid part of the
Memory bar shows the
fraction of the
acquisition that is
displayed.
Figure 37
Ensuring Accurate Measurements
Time base and Acquisition
132