Agilent Technologies 3458A User Manual page 353

digitizing, two additional commands are used for direct sampling and
subsampling: SWEEP which is related to NRDGS, and SSRC which selects the
trigger source (level or external) for subsampling. You can choose from a variety
of events or conditions that must be satisfied before taking measurements, as
shown is Figure 54. The default condition for all three levels of triggering is
AUTO; the 3458A will generate its own trigger as fast as the multimeter set-up
allows.
Figure 54. The trigger
event choices shown
provide the versatility
needed to match a wide
variety of applications.
TARM is the first condition to be satisfied. Its function is to arm the trigger circuit
prior to receiving the trigger signal. For example, if a synchronizing signal were
available external to the signal of interest, then TARM EXT could be used to arm
the 3458A to look for the trigger event. Also, TARM can be used to control
multiple measurement sequences by adding the number of times you want a
particular measurement cycle repeated. For example, TARM SGL,4, specifies that
the trigger arming be applied four times and then stops. Refer to Figure 55.
Figure 55. Digitizing
with the standard
triggering command.
Trigger Arming, TARM
SGL, 4 allows a
measurement cycle to
occur only 4 times,
reducing the amount of
data necessary to
determine the ratio of
the shaded areas in the
input wave form.
Appendix E High Resolution Digitizing With the 3458A
10 OUTPUT 722; "TARM HOLD"
20 OUTPUT 722,"TRIG EXT"
30 OUTPUT 722, "NRDGS 5, TIMER"
40 OUTPUT 722; "TIMER 2E-3"
¼
200 OUTPUT 722; "TARM SLG, 4"
! Places the 3458 in a
measurement hold condition.
! Sets the trigger event to
trigger.
! Sets up a burst of five
readings for every trigger.
! The time between readings
will correspond to the
TIMER setting(2E-3 or 2 ms)
! Four burst of measurements
are allowed to begin when
the external triggers occur
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