Chapter 7 SCPI
The Measurement subsystems
242 WCDMA Options Version 6.20
PRINT #scpi, “:MEAS:GSM:ARR:RFTX:ALL? 2”
INPUT #scpi, result$
index = 0
result$ = result$ + “,”
DO
‘ Find the position within result$, where the first
comma appears
P = INSTR(result$, “,”)
’ Read out the part of result$ in front of the first
comma and convert it into a numeric value
result(index) = VAL(LEFT$(result$, P – 1))
’ Cut off the value just read from result$
result$ = MID$(result$, P +1))
index = index + 1
LOOP UNTIL result$=””
:MEAS[:CONT]:BLOCkdata The
BLOCkdata command element of this subsystem is used to read out all the
single measurement results necessary to generate the following result graphics:
– shape of the TX burst (burst received by the 4400 from the mobile)
–phase error
– modulation spectrum of burst received by the 4400 from the mobile
– AF spectrum (the audio spectrum)
:MEASure:BLOCkdata:BURStshape
This command starts a continuous measurement of the mobile’s burst.
The corresponding result string (to be read out either with the query form of the
command or with
:FETCh:BLOCkdata:BURStshape will contain
711 floating point real numbers, representing the measurement result values. The
numbers will only have one digit behind the dot. The single measurement result
values are separated by commas.
The meaning of the single values within the result string is as follows:
– The first two values are necessary for the scaling of the data. All remaining
709 values represent the measurement results.
– The first value (index = 0) gives the offset of the middle of the burst (bit 73)
in respect to the measurement result array.
Example: An offset of
353.0 means that the middle of the burst will be the
355
th
value within the array (or the value contained at index 354).
– The second value (index = 1) gives the peak power level of the burst in dBm.
– All following values (indices 2 to 710) give the RF power levels of the related
positions.
The resolution on the time axis is approx. 0.875 microseconds (i.e. the distance
in time between two consecutive measurement points).
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