The PFER measurement performs a narrow-band (<200 kHz) measurement of the modulation quality and frequency accuracy of the mobile station's transmitter. The test set measures frequency error, rms phase error and peak phase error over the useful part of the burst.
The PFER measurement demodulates the data and compares the measured wave form with the "ideal" waveform that was expected for the data received. The frequency error is the difference in frequency, after adjustment for the effect of the modulation and phase error, between the RF transmission from the mobile station and the test set. The phase error is the difference in phase, after adjustment for the effect of the frequency error, between the mobile station and the theoretical "ideal" transmission. This measurement conforms to ETSI GSM 05.05; and ETSI GSM 11.10, section 13.1.
The PFER measurement demodulates the guard bits according to the Tail Bit Demodulation parameter setting. This parameter determines how the PFER measurement performs demodulation on the guard bits, which in turn impacts the demodulation of the tail bits. For details on the settings available for this parameter, see SETup:PFERror:TBDemod .
You can measure one of the six adjacent uplink bursts of the multislot configuration at any one time. You can specify the burst to measure using CALL:(PDTCH|PDTChannel):MSLot:MEASurement:BURSt . The relative power level is within 30dB according the data sheet.
For GPRS mobiles, this measurement conforms to ETSI GSM 05.05 (Ver 8.2.0, 7.2.0, 6.6.0), section 4.6.1. It also conforms with 3GPP 51.010 (formerly ETSI GSM 11.10) if used as part of a type approval system.
For EGPRS mobiles, the Phase and Frequency Error measurement conforms to 3GPP 51.010 (formerly ETSI GSM 11.10), section 13.16.1. You can control the modulation and coding scheme (either 8PSK or GMSK modulation) used by the data connection to be measured using CALL:(PDTCH|PDTChannel):MCSCheme . Additionally, you can manually control what modulation should be expected for individual bursts using CALL:MODulation[:FORMat]:CONTrol:AUTO . See Modulation Format Control (EGPRS only) for more information.
The PFER measurement is controlled by the DSP in the test set. No calibration is required by the user, the DSP gets calibration information during test set power up. PFER measurements can be initiated with any measurement made by the test set.
All of these results are available using the FETCh command. If the most positive and the most negative frequency error are the same value, the most positive frequency will be returned. Worst frequency error is only accessible through GPIB. The test set always has an integrity indicator available regardless of whether it is a single or multiple burst measurement.
Auto triggering is the recommended trigger source for each measurement allowing the test set to choose the preferred trigger source. However, you may want to select the trigger source. Immediate trigger source is not recommended for PFER measurements.
|Recommended Trigger Source|
|Protocol or RF Rise|
|Protocol or RF Rise|
|RACH burst with mobile station in active cell mode (GSM only)||Protocol or RF Rise|
The PFER measurement provides you with a choice for the time reference (burst synchronization). (See Burst Synchronization of Measurements ). For GPRS and EGPRS mobiles, you should note that only the Midamble synchronization method is available when you set the multislot configuration to D2U2 (2 downlink timeslots, 2 uplink timeslots). For more details on setting the multislot configuration, see CALL:(PDTCH|PDTChannel):MSLot:CONFig .
|References measurement timing to the midamble transmitted within a timeslot.|
|The amplitude rise and fall of a transmitted burst determines the measurement time reference.|
|No edge of the burst is detected, the measurement is made using the first 87 or 147 bits of data found centered around the middle of the expected burst position. Can be used when measuring non-bursted signals|