The External Trigger Mode; The Internal Trigger Mode - HP 7090A Operator's Manual

The External Trigger Mode

The external trigger mode provides external (remote) triggering of record­
.
ings. To select the external trigger mode, use the trigger mode selector to
'
light the EXTERNAL
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After selecting the external mode, a search for the external trigger is ini­
tiated by pressing
buffered recording). Recording can then be triggered by supplying a falling
1
edge (logic to 0)
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(external trigger) connector on the right side panel.
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Post- or pre-trigger time settings may be used for externally triggered, buf­
fered recordings. However, only post-trigger time settings may be specified
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for externally triggered, direct recordings (prc-trigger selections are
ignored).
The EXT TRIG
pulled high (logic 1 at 5-volt
the external trigger mode, a TfL-Ievel transition from high to low (logic 1
to 0) applied to the
ing may also be triggered by contact closure of the positive terminal of the
connector to the connector's ground terminal.

The Internal Trigger Mode

With the internal trigger mode, you can specify signal voltage and slope
, t
requirements that must be met by the Channel ! input to trigger a record­
ing. After specifying the requirements and initiating a trigger search, the
HP 7090 continuously monitors the Channel ! input until the signal meets
the requirements, at which time triggering occurs. Although triggering is
via the Channel l input only, any of the channel inputs may he selected for
-
recording in the direct recording mode, and all of the channel buffers are
filled normally for the buffered recording mode.
Post- or pre-trigger time settings generally may be used for internally trig­
gered, buffered recordings. Only post-trigger time settings, however, may
he used for internally triggered direct recordings (pre-trigger times are
ignored).
Four internal trigger options are available - above level, below level, out­
side window, and inside window. Select the desired option by using the
trigger mode selector to light the appropriate indicator. The
and
TRIGGER WIDTH
signal requirements, as described in.the following sections.
\J
j
indicator.
(for a direct recording) or
DIRECT RECORD
'TT L level or contact closure to ground to the
connector accepts a male BNC connector, and is normally
level). After initiating a trigger search in
TTL
EXTTRIG connector will trigger the recording. The record­
setup conditions are then used to define the Channel !
FILL BUFFER
TRIGGER LEVEL
Scans by ArtekMedia © 2007
(for a
EXT
TRIG
The External
Trigger Connector
Trigger Modes and Operations 5-3