Averaging Acquisition Data - Fluke CombiScope PM3370B User Manual

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3.5 Averaging Acquisition Data

Acquired traces and measured signal characteristics can be averaged over a
number of acquisitions. The preprocessing AVERAGE function of the
CombiScopes instruments can be enabled by using the SENSe:AVERage[STATe]
command. When this function is set to ON, averaging is done according to the
following formula:
∑
(
AVG =
n
In the expression, n specifies the number of acquisitions that is averaged. This
parameter can be programmed by using the SENSe:AVERage:COUNt
command. X represents the acquisition result to be averaged.
Example:
→
Send SENSe:AVERage:COUnt 16
→
Send SENSe:AVERage ON
When SENSe:AVERage is set to ON and an acquisition is initiated, the
CombiScope instrument takes n (SENSe:AVERage:COUNt) successive
acquisitions, as shown in the figure on the next page. When sufficient acquisitions
are taken, the final averaged result is returned. Intermediate results cannot be
queried.
PROGRAM EXAMPLE:
Acquire the trace of the actual signal on channel 1 and measure the amplitude
and frequency (averaged over 4 acquisitions).
DIM trace AS STRING * 1033
DIM amplitude AS STRING * 10
DIM frequency AS STRING * 10
CALL Send(0, 8, "CONFigure:AC (@1)", 1)
CALL Send(0, 8, "SENSe:AVERage:COUNt 4", 1)
CALL Send(0, 8, "SENSe:AVERage ON", 1)
CALL Send(0, 8, "INITiate", 1)
CALL Send(0, 8, " * WAI;TRACe? CH1", 1)
CALL Receive(0, 8, trace$, 256)
'The trace samples are averaged over 4 sequential trace acquisitions.
CALL Send(0, 8, "READ:AMPLitude?", 1)
CALL Receive(0, 8, amplitude$, 256)
CALL Send(0, 8, "FETCh:FREQuency?", 1)
CALL Receive(0, 8, frequency$, 256)
'The amplitude and frequency are averaged over 4 sequential measured values.
) n ⁄
X + + .. X
1 n
USING THE COMBISCOPE INSTRUMENTS
' This sets the average count factor at
16, which means 16 sequential
acquisitions are averaged.
' This enables the AVERAGE function.
'Dimensions trace string
'Dimensions amplitude string
'Dimensions frequency string
'Configures for AC-RMS
'Average factor = 4
'Averaging is turned on
'Initiates the averaging acquisition
'Queries for channel 1 trace
'Enters channel 1 trace
'Reads the amplitude
'Enters the amplitude
'Fetches the frequency
'Enters the frequency