HP 54750A, User Manual, Page: 186 / 478

Trigger Menu
This section describes the Trigger menu, and explains how you can use its
controls to trigger the instrument. The trigger circuit performs two functions .
It locates the waveform of interest, and it synchronizes the instrument
measurement and display to the waveform.
Trigger Basics
A trigger event is dened as an edge of a selected slope (either positive or
negative) that transitions through a selected voltage (trigger level).
The trigger circuit and sampler circuit operate in parallel. The sampler
samples the input signal at a specic rate . The trigger circuit operates
independently of the sampler circuit, and a trigger event does not have to
occur at the same time as a sample point. Because the instrument knows
when the trigger event happened in relation to the sampled data, the
instrument knows where to place the sampled data on the display .
There are three green LEDs at the top left corner of the mainframe .
When a LED is lit, it indicates the trigger status of the instrument.
Armed The instrument is waiting for a trigger event to occur .
Triggered The instrument triggered on a valid trigger event.
Freerun The instrument is automatically triggered as soon as it is
armed. This is useful for seeing a waveform untriggered or
for looking at a baseline .
HP 83480A Option 100 only: When in the 12 GHz mode , the triggered and
freerun lights are illuminated at all times to reect the operation of the 12
GHz trigger .
Refer to the User's Reference for the plug-in you are using for details on the
trigger specications .
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