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Receiver Control
Last updated: May 8, 2002
Receiver Control is applicable to both GSM and GPRS. This topic contains the following sections:
GSM Receiver Control
You may want to control the internal receiver parameters rather than allow the test set to control them. You can do this by using the receiver control parameters.
Selecting Manual or Automatic Receiver Control
Receiver control defines whether the test set (auto) or you (manual) are in control of the receiver's band, channel, frequency and power.
-
Setting a manual band, manual frequency, or manual channel causes receiver control to be set to manual control mode.
-
Setting the broadcast band, or any reset operation causes the receiver control to be set to auto control mode.
-
Setting the RFANALYZER:CONTROL:AUTO to ON or OFF.
Example
OUTPUT 714;"RFANALYZER:CONTROL:AUTO OFF" !Allows manual control of
!receiver parameters.
Operating Mode and Receiver Control
The test set's receiver control parameter is set using,
RFANalyzer:CONTrol:AUTO
.
Manual Receiver Control Parameters
When receiver control is set to auto, the test set's protocol controls the parameters. When receiver control is set to manual, the following three parameters are under user control.
-
Manual Band
-
Manual Freq
-
Manual Channel
Manual Band
The frequency bands available for the test set are PGSM, EGSM, GSM450, GSM480, GSM750, GSM850, DCS, PCS and RGSM. Only one band can be active at a time. The frequency band must be selected in order to define the frequencies where measurements are to be made. See
Frequency Banded Parameters
for details on these parameters.
OUTPUT 714;"RFANALYZER: MANUAL:BAND PCS"!Sets the frequency band to PCS.
Manual Freq
Manual frequency is used to tune the test set's measuring receiver. None of the
Manual Channel
parameters are affected by changes to manual frequency.
OUTPUT 714;"RFANALYZER:MANUAL:FREQUENCY 942.6MHZ" !Sets the input frequency to 942.6 MHz.
Manual Channel
Manual channel is used to tune the test set's measuring receiver.
Manual Freq
is affected by changes to manual channel.
OUTPUT 714;"RFANALYZER:MANUAL:CHANNEL:EGSM 24" !Sets the EGSM channel to 24.
Manual Receiver Control
If the receiver control parameter is set to manual, the test set's receiver frequency is set using the parameters in the following table. See
RFANalyzer:MANual:BAND
for manual band or manual frequency details.
Test Set Receiver Frequencies (Manual)
|
Operating Mode |
Cell Activated State |
Measurement Band |
Measurement Frequency |
Measurement Channel |
|
Active Cell
|
ON or OFF |
Manual Band |
Manual Frequency |
Manual Channel |
|
Test Mode
|
ON or OFF
|
Manual Band |
Manual Frequency |
Manual Channel |
Auto Receiver Control
If the receiver control parameter is set to auto, the test set's receiver frequency is set using the parameters in the following table. See
CALL:TCHannel[:ARFCn][:SELected]
traffic channel details and
CALL:TCHannel:BAND
for traffic band details. See
CALL[:CELL]:BAND[:SELected]
for cell band details. See
CALL:BCHannel
for broadcast channel details.
Test Set Receiver Frequencies (Auto)
|
Operating Mode
|
Cell Activated State
|
Measurement Band
|
Measurement Frequency
|
|
Active Cell
|
ON
|
Traffic Band
|
Traffic Channel
|
|
Active Cell |
OFF
|
Cell Band
|
Broadcast Channel
|
Test Set Receiver Frequencies (Auto)
|
Operating Mode
|
Test Function
|
Measurement Band
|
Measurement Frequency
|
|
Test Mode
|
BCH (1)
|
Cell Band
|
Broadcast Channel
|
|
Test Mode |
BCH +TCH (2)
|
Traffic Band
|
Traffic Channel
|
|
Test Mode
|
CW
|
Cell Band
|
Broadcast Channel
|
Table Footnotes
|
1
|
Actual frequency depends on current broadcast band (PGSM, EGSM, GSM450, GSM480, GSM750, GSM850, PCS, DCS or RGSM) and is defined in GSM as the uplink frequency.
|
|
2
|
Actual frequency depends on current traffic channel band (PGSM, EGSM, GSM450, GSM480, GSM750, GSM850, PCS, DCS or RGSM) and is defined in GSM as the uplink frequency.
|
Expected Power
You can use the expected power parameter regardless of the receiver control setting. The MS TX level parameter sets the mobile station uplink power control level ranges while expected power sets the mobile station uplink power in dBm.
Expected power defines the expected input power at the RF IN /OUT connector on the front panel of the test set. The range of expected power is beyond the capability of the test set's hardware. This is because expected power is intended to reflect the potential range of RF power at the DUT. This range of RF power is meant to accommodate the use of a gain or loss network between the DUT and the test set. See
Amplitude Offset
for details about amplitude offset.
The upper and lower limits of expected power provide boundaries for the combination of amplitude offset and expected power. If the user sets expected power to +52 dBm and the amplitude offset to -3 dB, the calculated receiver power will be 49 dBm, but the test set shall be set to +43 dBm, the upper limit of the hardware. If the calculated value of receiver power goes below -25 dB, the lower limit of the hardware, the test set shall be set to -25 dB.
Expected power is always overwritten by settings made to the MS TX Level parameter.
Setting the expected power will not set receiver control to manual.
OUTPUT 714;"RFANALYZER:EXPECTED:POWER:PGSM -15DBM" !Set input power to -15 dbm.
See
RFANalyzer:EXPected:POWer:PGSM
or
CALL:MS:TXLevel[:SELected]
.
GPRS Receiver Control
The test set normally sets all receiver parameters automatically using data connection control settings. You may want to control the test set's receiver parameters manually rather than allowing the test set to control them. This ability is referred to as manual receiver control.
Selecting Manual or Automatic Receiver Control
-
Auto mode is the default for all operating modes. The receiver's expected power and measurement frequency settings are set automatically according to the data connection control settings you specify (Packet Data Traffic Channel, Packet Data Traffic Band, and MS TX Level).
-
Manual mode allows you to override some or all of the automatic settings by first selecting the manual mode for the setting and then specifying the desired value. You can view the affected settings by selecting F12 (Receiver Control) from the Call Setup screen. A full or partial preset of the test set, including cycling power, returns the test set back to auto mode.
GPIB Examples
The following program examples use simple commands to perform a single function. Complex commands that enable manual receiver control and set a specified parameter at the same time are also available. See
RFANalyzer
for a listing of all receiver control syntax. (Note that some of the commands described in
RFANalyzer
are GSM only.)
OUTPUT 714;"RFANalyzer:CONTrol:MEASurement:FREQuency:AUTO OFF" !Enables manual control of the measurement receiver's frequency.
OUTPUT 714;"RFANalyzer:MANual:MEASurement:FREQuency 825.030 MHZ" !Tunes the measurement receiver to 825.030 MHz through manual receiver control.
OUTPUT 714;"RFANalyzer:CONTrol:MEASurement:FREQuency:AUTO ON" !Returns measurement receiver frequency tuning control to auto.
Manual control parameter values are stored internally (as long as the test set is powered on). Enabling manual control of a parameter without providing a new value causes a previously stored value to immediately take effect. This allows you to pre-define manual control parameter values in your program before enabling manual control.
Operating Mode and Receiver Control
Manual Receiver Control Parameters
The following parameters can be used to control the receiver manually:
-
Expected Power Control
-
Measurement Frequency
-
Uplink Frequency
-
Measurement Burst
Expected Power Control
The expected power from the mobile is set manually using the following settings (see
Expected Power
):
-
To set the test set receiver's expected power setting to manual use
RFANalyzer:CONTrol:POWer:AUTO
.
OUTPUT 714;"RFANalyzer:CONTrol:POWer:AUTO OFF"
-
To set the power level that the test set's receiver is expecting the mobile station uplink burst to transmit at for the GPRS system type, use
RFANalyzer:MANual:POWer:GPRS[:SELected]:BURSt[1|2]
. Each burst is set individually.
OUTPUT 714;"RFANalyzer:MANual:POWer:GPRS:BURSt1 15 DBM"
OUTPUT 714;"RFANalyzer:MANual:POWer:GPRS:BURSt2 19 DBM"
During manual receiver control, make sure you are using the correct operating mode for the type of measurement you are making. Trying to measure a CW signal while in active cell mode will likely result in an error. This error occurs because the test set uses the expected power setting for the operating mode you are using, and uses different methods to measure analog and digital signals.
It is recommended that you specify the expected power each time you perform a handoff to a new band or traffic channel type during manual receiver control. This ensures that the correct expected power is set for the new channel settings.
Measurement Frequency
Measurement frequency is used to tune the test set's measuring receiver for all bands:
Uplink Frequency
Uplink Frequency sets the test set's demodulation receiver frequency, used to demodulate information from the mobile's uplink transmission:
Manual control of the demodulation receiver frequency is rarely needed. Use the measurement receiver when manual receiver frequency control is required. Automatic control is always used when the cell operating mode is active cell.
Measurement Burst
Measurement Burst sets the mobile uplink burst number on which the measurement is performed (not the absolute timeslot number, but the burst number relative to the first uplink burst in the TDMA frame):
-
To set the measurement burst use
RFANalyzer:MSLot:MEASurement:BURSt
.
OUTPUT 714;"RFANalyzer:MSLot:MEASurement:BURSt 2" !Sets the receiver to measure the second uplink !burst.
The Measurement Burst parameter is always controlled manually. The choice of bursts available is based on the selection table shown under the multislot selection command,
CALL:PDTCH:MSLot:CONFiguration
.
Auto Receiver Control
The receiver settings are derived from the following parameters when using automated control:
-
Expected Power - derived from the MS TX Level setting for the specified system type, queried/set using the following command:
-
Measurement Frequency and Link Frequency - derived from the PDTCH Band and PDTCH (ARFCN) settings, queried/set using the following command:
Expected Power
To make accurate measurements, the test set needs to know how much power to expect at the test set's RF IN/OUT port; referred to as the Expected Power. It gets this value from the call control MS TX Level setting during automatic receiver control, or by the user specifying the expected power with the receiver power control set to manual. See
Expected Power Control
for more information.
You can set the expected power level beyond the capability of the test set's hardware because expected power is intended to reflect the potential range of RF power
at the DUT
. This range of RF power is meant to accommodate the use of a gain or loss network between the DUT and the test set. See
Amplitude Offset
for details about amplitude offset.
The upper and lower limits of expected power provide boundaries for the combination of amplitude offset and expected power. If you set expected power to +52 dBm and the amplitude offset to -3 dB, the calculated receiver power will be 49 dBm, but the test set shall be set to +43 dBm, the upper limit of the hardware. If the calculated value of receiver power goes below -25 dB, the lower limit of the hardware, the test set shall be set to -25 dB.
Effects on Receiver Control When Changing Operating Mode
After selecting the operating mode to use and setting one or more receiver controls to manual, the receiver control settings remain as you set them until you change operating mode. Changing operating mode causes all receiver parameters to return to automatic control.
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