3 VMA Mode
3.4 IQ Waveform Measurement
Time Avg Num
Sets the number of HW averages to be executed per each data acquisition.
HW Averaging
Changes the number of time averages to be made using hardware. This averaging is
much faster than the standard averaging done in software. The hardware averaging
is done on the complex voltage time trace data before any measurement application
averaging is done. Both types of averaging (HW and SW) can be done on the same
measurement data.
When time averaging is being done in HW, each trace update represents N fresh
data acquisitions averaged together, where N is the number of time averages. You
cannot access the individual time data. Note that this averaging is done prior to the
SW averaging done within the application. Thus, if time averaging is turned on, the
trace in this measurement shows the result of HW averaging even if the normal (SW)
averaging is turned off. Subsequent normal (SW) averaging is orthogonal to this
hardware-based time averaging.
Thus, it is possible to turn off normal (SW) averaging within the application but still
have the HW averaging set to a certain number greater than 1. In other words,
turning averaging off within the measurement will not affect HW averaging. If HW
averaging needs to be turned off, simply set the HW Averaging parameter to 1.
The Auto/Man feature of Time Avg Num works differently than other parameters.
Since it is time averaging, a trigger source something other than Free Run should be
used to synchronize successive data acquisitions to avoid cancelling out the signal
to be measured. It is most useful for a periodic signal with known periods used in
conjunction with the Periodic trigger. Thus, when in Auto, the Trigger Source
automatically changes to Periodic trigger when Time Avg Num is turned ON. The
trigger period is set to the current Meas Time value. Any changes to Meas Time
change the Periodic trigger period to the same value and vice versa. If a trigger
source other than Periodic trigger is manually selected, the Time Avg Num
Auto/Man toggle is set to Man.
Remote
Command
[:SENSe]:WAVeform:AVERage:TACount <integer>
[:SENSe]:WAVeform:AVERage:TACount?
Example
:WAV:AVER:TAC 10
:WAV:AVER:TAC?
Notes Only available when Option DP2, B40, or wider IF Bandwidth option is installed
Preset 1
State Saved Saved in instrument state
Min/Max 1/65535
759 Vector Modulation Analyzer Mode User's &Programmer's Reference
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