Post- And Pre-Trigger Time - HP 7090A Operator's Manual

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Post- and pre-trigger time selections can be extremely useful for certain
applications. For example, by selecting an appropriate post-trigger time,
you can :set the HP 7090 to begin recording data at a specified time after the
occurrence of a trigger. Pre·trigger times can be used to capture data in the
buffers for events that
event. The following section describes the post- and prc-trigger setup condi­
to
tion used
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The P08t Trigger / Pre Trigger Setup Condition
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l =
Default Value:
Range of Selectable V alues:
Pre-trigger selections disp
sign. The selectable time increments for prc- and post-time settings are
dependent upon the
smaller selectable time increments.
For the default setting of 0.0 seconds (no prc- or post-trigger time) recording
begins the moment a valid trigger is received. However, all trigger modes
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(except internal with the inside-window option) are subject to post-trigger
time selections.
elapse after triggering before recording occurs.
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Pre-trigger time,
triggered, buffered recordings.
tion of TOTAL TIME
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occurring immediately before the trigger. Refer
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With a pre-trigger time specified, the buffers begin filling as soon as you
press FILL BUFFER.
has elapsed, at which time the buffer contents are continuously updated
until the valid trigger arrives. Upon arrival of the trigger, the data cur­
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rently captured in the buffers (representing the prc-trigger time) is frozen,
and the remaining buffer space is filled. If the trigger occurs
specified prc-trigger time has elapsed, the pre-trigger time is cut short and
the buffers are allowed
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MEASUREMENT INITIATED
(FILL BUffER PRESSED]
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occ u rred
immediately
select post- or pre-trigger times .
0.0 seconds .
0.01 second to 24 hours (post-trigger).
-0.01 second to-24 hours (prc-trigger).
a ed on
l y the
TOTAL TIME setting - smaller total time settings allow
Post-trigger time is the amount of time delay that must
on the other hand, applies only to internally or externally
A
prc-tigger time value specifies what por­
is to be used for storing digitized input signal data
They continue filling until the specified pre-trigger time
to fill .
TRIGGER
OCCURS
PRE·TRIGGER
DATA
PRE·TRIGGER TIME .... ..
TOTAL TIME
(BUFFER FILL TIMEI
CHANNEL
BUFFER
before a selected triggering­
are
LeO
preceded by
to the following illustration.
RECORDING ENDS!
MEASUREMENT COMPLETE
POST-TRIGGER
DATA
Scans by ArtekMedia © 2007
Post- and Pre
Trigger Time
-
minus ( )
a
before the
Capturing Pre-Trigger Data
ina Buffer
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