R&S FSL Averaging I/Q Data
1300.2519.12 7.23 E-11
CALL viRead(analyzer, result$, 1, retCount)
'Read in end character <NL>
'––––––––– Output of binary data as frequency/level pair –––––––––––––––––
IQValues = IQBytes/4 'Single Precision = 4 Bytes
F
or i = 0 To IQValues – 1
Print "I–Value["; i; "] = "; IData(i)
Print "Q–Value["; i; "] = "; QData(i)
Next i
'––––––––– Read–out in ASCII format ––––––––––––––––––––––––––––––––––––––––
CALL InstrWrite(analyzer,"FORMAT ASCII") 'Set ASCII format
CALL InstrWrite(analyzer, "TRAC:IQ:DATA?")
'Re–measure and read out
'I/Q data
CALL InstrRead(analyzer, asciiResult$)
CALL InstrWrite(analyzer,"TRAC:IQ:STAT OFF")
'Stop I/Q data aquisition
'mode if no further
'measurements are to be
'done
END SUB
REM ************************************************************************
Averaging I/Q Data
The R&S FSL has averaging capability also for I/Q measurements, i.e. I/Q data can be averaged over
several test runs. This is subject to the following conditions:
1. An external trigger signal must be available for data measurement, and the trigger signal must be
phase–locked to the signal measured.
2. The same reference–frequency signal must be used for the DUT and the R&S FSL.
3. The sampling rate must be 32 MHz, since only with this sampling frequency will the measurement
be performed phase–synchronous with the trigger signal.
If all of the above conditions are fulfilled, no phase shift will occur between consecutive test runs. Phase
shift may falsify the measured average so that in extreme cases a value of 0 is obtained.
The default setting of the instrument for data measurement without averaging has to be changed as
follows:
REM ************************************************************************
'––––––––– R&S FSL default setting ––––––––––––––––––––––––––––––––––––––––
CALL SetupInstrument 'Default setting
CALL InstrWrite(analyzer,"TRAC:IQ:STAT ON")
'Activate I/Q data acquisition
'mode; this must be
'done before TRAC:IQ:SET!
'Select max. number of test points (= 512 * 1024 – 512) at 10 MHz RBW,
'32 MHz sampling rate, external
'trigger, pos. trigger edge and
'0 s trigger delay.
CALL InstrWrite(analyzer,"TRAC:IQ:SET NORM,10MHz,32MHz,EXT,POS,0,130560")
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