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S:\Hp8960\E1962B CDMA 2000\Pi Release\Reference Guide\Chapters\cdma2000_prog_trig.fm
Triggering of Measurements
Triggering of Measurements
Trigger Source Choices
For cdma2000, no user control of trigger sources is available. (Some test applications provide measurements
with multiple trigger sources, as described below.) The only trigger sources that are used by cdma2000 are:
• “RF Rise Trigger Source:”
• “Immediate Trigger Source:”
Refer to “Measurements” for cdma2000 measurement-specific triggering information.
Refer to “Triggering Process Description” for a generic description of triggering measurements.
Description
Trigger Source Description
A measurement trigger causes hardware (for example, a sampler) to capture data which is used by a
measurement algorithm to produce a measurement result. Not all of the trigger source choices are available in
every measurement, or every test application.
RF Rise Trigger Source: When RF rise triggering is selected, a measurement dependent threshold is used
to define the trigger point on the envelope of the signal being measured. The envelope amplitude must fall
below this threshold and remain there for a measurement-dependent period of time before the trigger is
armed. After the trigger is armed, a trigger will occur as the envelope amplitude increases and passes through
the threshold.
Protocol Trigger Source: When protocol triggering is selected, a data capture is triggered by a protocol
generated signal. The test set’s protocol engine knows when the DUT’s signal should be present and generates
a trigger signal for use by the measurement to trigger the data capture.
External Trigger Source: When external triggering is selected, the user supplies an external trigger signal
via the rear panel TRIG IN connector in order to trigger data capture. The trigger will occur on the rising edge
of this signal.
Immediate Trigger Source: When immediate triggering selected, the trigger occurs as soon as any
pre-trigger samples required by the measurement algorithm are taken. Data capture is triggered when the
measurement is initiated.
Auto Trigger Source: When auto triggering is selected, the test set automatically chooses the best trigger
source for that measurement. This trigger source setting is convenient because the measurement trigger
doesn’t need to be changed when switching parameters. Auto trigger source is the best choice for most users.
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