Operating instructions

More Complex Programming Examples R&S ESCI
1166.6004.12 7.42 E-1
Averaging I/Q Data
The R&S ESCI 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 ESCI.
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 invalidate 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:
'--------- R&S ESCI default setting ----------------------------------------
--
CALL SetupInstrument 'Default setting
CALL IBWRT(receiver%,"TRAC:IQ:STAT ON") 'Activate I/Q data acquisition
'mode; this must be
'done before TRAC:IQ:SET!
'Select max. number of test points (= 128 * 1024 – 512) at 10 MHz RBW,
'32 MHz sampling rate, external trigger, pos. trigger edge and 0 s trigger
'delay.
CALL IBWRT(receiver%,"TRAC:IQ:SET NORM,10MHz,32MHz,EXT,POS,0,130560")
CALL IBWRT(receiver%,"TRAC:IQ:AVER ON") 'Switch on I/Q averaging
CALL IBWRT(receiver%,"TRAC:IQ:AVER:COUN 10") 'Set 10 test runs
'--------- Read data in binary format --------------------------------------
...