HP 54620A User's And Service Manual page 77

Making Analyzer Measurements
To define an advanced trigger
are trying to capture and understand how the advanced trigger capabilities
relate to those events.
Setup rules
Remembering the following rules will make it easier to work with the
advanced triggering capabilities:
•
Duration operators are valid when only pattern terms are involved.
Duration is not selectable when any edge terms are selected as a source.
Occurrence operators are valid only when at least one edge term is
involved. Occurrence is not selectable when only pattern terms are
selected as a source.
•
When you have selected a combination source, like Pat_1 AND Edge1, you
cannot directly define the pattern or edge. You must instead select Pat_1
as the source, define the pattern, then select Edge1 as the source and
define the edge. The softkeys change to reflect this.
Understand the waveform events and relate them to analyzer
capabilities
The key to setting up a useful waveform display is picking a known sequence
of waveform events to which you can apply the advanced trigger capabilities
of the HP 54620A/C.
To find these events, you can ask a series of questions about the waveform,
keeping in mind the capabilities of the analyzer.
•
Does the input data always repeat with respect to a particular waveform's
high or low period of constant duration?
•
Is there a sequence of waveform events that define the data of interest?
For example, is there a state machine, where the hypothetical sequence
"aac" leads to the events of interest, where "aab" does not?
•
Are the events of interest defined by a certain number of iterations of a
circuit? For example, does the circuit fail (producing the events of
interest) on the 38th iteration of a data pattern and edge combination?
Usually, you will want to set the analyzer to Normal trigger mode so that you
see a display only when the trigger condition occurs. However, you might
want to use Auto trigger mode while experimenting with the trigger
definition so you can see a display of the data that is captured by the analyzer.
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