Programming a Frequency Modulation (FM) Measurement

Last updated: August 12, 2005

The following program example assumes that the mobile's antenna output is connected to the RF IN/OUT connector, and the mobile is on an analog voice channel (AVC).

The test set uses the AVC Channel (CALL:SET:AVC) and MS TX Level (CALL:SET:MS:ANALog:TXLevel) settings of the base station emulator for the expected frequency and power level. To manually set the expected frequency and power, see Receiver Control .

General Programming Procedure

Enter the expected frequency and power.
Configure the Frequency Modulation setup parameters using SETup:FM subsystem.
Start the measurement using the INITiate subsystem.
Obtain the measurement results using the FETCh:FM subsystem to obtain the measurement results.

Programming Example

 
10  !Set the expected frequency and power.
20  OUTPUT 714;"SETup:FM:COUNt 5" !Set multi-measurements to 5.
30  OUTPUT 714;"SETup:FM:DISTortion:STATe ON" !Enable the distorion measurement.
40  OUTPUT 714;"SETup:FM:DISTortion:FREQuency 1004 HZ" !Set the distortion measurement
50                                                    !Fundamental Frequency (1004 HZ).
60  OUTPUT 714;"SETup:FM:FREQ:STATe ON" !Turn on the modulation frequency measurement.
70  OUTPUT 714;"SETup:FM:FILTer CMESsage" !Select the C-Message filter.
80  OUTPUT 714;"SETup:FM:DETEctor PPEak" !Select the Peak + detector.
90  OUTPUT 714;"SETup:FM:DEMPhasis:STATe OFF" !Make sure de-emphasis is off.
100 OUTPUT 714;"SETup:FM:EXPandor:STATe OFF" !Make sure the expandor is off.
110 OUTPUT 714;"SETup:FM:CONTinuous OFF" !Set the FM measurement to single trigger mode.
120 OUTPUT 714;"SETup:FM:TIMeout 1 S" !Set a timeout value of 1 second
130                                   !in case the measurement cannot be made.
140 OUTPUT 714;"INITiate:FM" !Start the measurement.
150 OUTPUT 714;"FETCh:FM?" !Query the returned integrity indicator and the
160        !average FM deviation and average FM distortion results.
170 ENTER 714;Integrity,Fm_dev,Fm_dist,Fm_freq !Enter the returned values into variables.
180 IF Integrity=0 THEN  !See if the integrity value = 0 (valid measurement).
190 ELSE
200 PRINT "Measurement problem; check for signal level over/under range condition."
210 END IF
220 END

Returned Values

The measurements returned by this program are:

Integrity returns the measurement integrity indicator (see Integrity Indicator ); 0 means a successful measurement with no errors.
FM_dev returns the average FM deviation in kHz. FM_dist returns the average FM distortion in percent (%). FM_freq returns the average modulation frequency in Hz.

Programming a Frequency Modulation (FM) Measurement

General Programming Procedure

Programming Example

Returned Values

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