To Use The External Trigger Input - HP 54620A User's And Service Manual

Making Analyzer Measurements

To use the external trigger input

To use the external trigger input
Connect a signal to the BNC labeled "Ext trigger in."
1
The "Ext trigger in" BNC is the rightmost one on the HP 54620A/C front
panel. It has an input impedance of 1 MΩ and can accept a maximum signal
of ±40 V. You can connect the trigger output of other instruments to the
external trigger input, or use an oscilloscope probe, such as the HP 10071A.
Set up the proper threshold voltage for the input using the Logic
2
levels menu.
See "To change the logic threshold for input signals." The external trigger
threshold is represented as
Set up an edge, pattern, or advanced trigger specification using the
3
external trigger input as part of the specification.
The external trigger input is labeled as "Ext" in the pattern, and is selectable
with either the Select knob or the Entry knob during pattern or edge
definition. See "To define an edge trigger," "To define a pattern trigger," or
"To define an advanced trigger."
The external trigger input is useful when it is not practical to completely
qualify the desired trigger pattern using only the logic inputs. For example,
you may want to trigger the analyzer only after another instrument has found
a trigger. Or, you may need to use all logic channels for input data, and need
just one additional channel for an edge trigger. Or, you may want to use a
scope probe to examine a system signal with larger signal swings than
allowed by the logic inputs.
108
under the
E Trg In Set
softkey.