User`s guide

1-8
Command Guidelines
Output RF Spectrum Modulation Reference Measurement Averaging
Output RF Spectrum Modulation Reference Measurement
Averaging
The Agilent 8922M/S makes the modulation reference measurement of the Output RF
Spectrum (ORFS) due to modulation test based on a single burst measurement. If you
wish to comply with the GSM Recommendation 11.10, then the following information
will be of interest.
The spectrum due to modulation portion of the GSM ORFS recommendation specifies
maximum levels of power, measured at given frequency offsets from the nominal carrier
frequency, relative to a reference measurement at the carrier frequency. The
recommendation calls for the reference measurement and all other measurements to be
averaged over 200 bursts.
To get averaged ORFS due to modulation measurement results relative to an averaged
reference as in GSM Recommendation 11.10, refer to the following example GPIB script:
!Make a single Modulation Reference measurement.
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:AVERage:STATe OFF”
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:REFerence:STATe OFF”
OUTPUT Gpib;”TRIGger:MODE ‘SINGLE’”
OUTPUT Gpib;”DISPlay:SCReen ORFS”
OUTPUT Gpib;”DISPlay:ORFSpectum:VIEW ‘MAIN’”
OUTPUT Gpib;”ORFSpectrum:MODE ‘MOD REF’”
OUTPUT Gpib;”TRIGger:ASTate ‘ARM’”
!Make 200 modulation measurements at 0 kHz offset and average them.
!This result is the correction factor to the single Modulation
!Reference measurement done earlier.
OUTPUT Gpib;”ORFSpectrum:MODE ‘MODULATN’”
OUTPUT Gpib;”ORFSpectrum:FREQuency:OFFSet 0 KHZ”
OUTPUT Gpib;”DISPlay:ORFSpectrum:VIEW ‘TRACE’”
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:AVERage:VALue 200”
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:AVERage:STATe ON”
OUTPUT Gpib;”TRIGger:MODE ‘CONT’”
WAIT 150
!The Agilent 8922M/S makes about 2 measurements per second.
!The Agilent 8922S must be allowed about 1600 seconds.
!This wait allows at least the needed 200 measurements
!to occur for averaging per GSM Recommendations.
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer?”
ENTER Gpib;Correction$
OUTPUT Gpib;”TRIGger:MODE ‘SINGLE’”
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:AVERage:STATe OFF”
!Enter the correction factor as the Reference value ( REF SET ) for the
!following measurements.
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:REFerence:VALue ”&Correction$
OUTPUT Gpib;”MEASure:ORFSpectrum:POWer:REFerence:STATe ON”
OUTPUT Gpib;”MEASure:RESet”
!The ORFS Modulation measurement is now ready for use.
!Do not forget to use averaging.