Programming a Modulation Accuracy Measurement
Last updated: December 3, 2008
This section is only applicable to EGPRS.
The following procedure assumes that the mobile station is connected to the test set's RF IN/OUT connector.
-
Change the serving cell to EGPRS. To do this via GPIB, you must first turn the cell off. See the following procedure.
-
Turn the cell off using the CALL:OPER:MODE OFF command.
-
Change the serving cell to EGPRS using the CALL:BCH:SCEL EGPRS command.
-
Turn the cell back on using the CALL:OPER:MODE CALL command.
-
Set the connection type to ETSI A using the CALL:FUNC:CONN:TYPE A command.
-
Set the modulation and coding scheme to one which uses 8PSK modulation.
-
Set up the modulation accuracy measurement parameters using the SETup:EMACcuracy parameters (See
SETup:EMACcuracy
for more information.)
-
Turn on the mobile station and allow it to attach.
-
Start the data connection.
-
Use a hanging query to determine when the connection has started and to provide synchronization between your program and the test set.
-
Initiate the modulation accuracy measurement.
-
Fetch the measurement results using a FETCh:EMACcuracy? query. (See
FETCh:EMACcuracy
for more information.)
Programming Example:
10 ! Turn the cell off to access the serving cell parameter
20 OUTPUT 714;"CALL:OPER:MODE OFF"
30 ! Change the serving cell to EGPRS
40 OUTPUT 714;"CALL:BCH:SCEL EGPRS"
50 ! Turn the cell back on
60 OUTPUT 714;"CALL:OPER:MODE CALL"
70 ! Set the connection type to ETSI Type A
80 OUTPUT 714;"CALL:FUNC:CONN:TYPE A"
90 ! Select a Modulation and Coding Scheme using 8PSK
100 OUTPUT 714;"CALL:PDTCH:MCSC MCS9,MCS9"
110 OUTPUT 714;"SET:EMAC:CONT OFF"!Set trigger mode to single
120 OUTPUT 714;"SET:EMAC:COUN 5"! Turn statisical results on
130 ! Turn measurement timeout on and set to 5 seconds
140 OUTPUT 714;"SET:EMAC:TIM 5"
150 !
160 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
170 ! Turn on the mobile station and allow it to attach
180 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
190 !
200 ! Start the data connection
210 OUTPUT 714;"CALL:FUNC:DATA:START"
220 ! Hanging query to determine when the data connection
230 ! has been established.
240 OUTPUT 714;"CALL:TRAN?"
250 ENTER 714;Tran_state
260 IF NOT Tran_state THEN
270 PRINT "DATA CONNECTION FAILED"
280 STOP
290 END IF
300 OUTPUT 714;"INIT:EMAC" ! Initiate measurement
310 ! The query below fetches the measurement results required
320 ! by the conformance specification for modulation accuracy.
330 OUTPUT 714;"FETC:EMAC:ETSI?"! Fetch measurement results
340 ENTER 714;Integrity,Rms_evm,Peak_evm,Percentile,Ferr,Origin_offset
350 END
Returned Values
The measurements returned by the FETCh? query in the programming example above are:
-
Integrity
returns the measurement
Integrity Indicator
(0 means a successful measurement with no errors).
-
Rms_evm
returns the RMS Error Vector Magnitude in percent.
-
Peak_evm
returns the Peak Error Vector Magnitude in percent.
-
Percentile
returns the 95th Percentile Error Vector Magnitude in percent.
-
Ferr returns the frequency error in hertz.
-
Origin_offset
returns the origin offset suppression in dB.
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