Gsm Phase Frequency Error
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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
What Is Phase Error
data and compares the measured wave form with the "ideal" waveform that was expected frequency error ppm for the data received. The frequency error is the difference in frequency, after adjustment for the effect of the modulation and phase frequency error definition 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
Phase Error Definition
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
Frequency Of Error In Test
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. Single or Multi-Measurements The DSP demodulates the data and compares the measured waveform with the "ideal" waveform created by the DSP. A single burst for a PFER measurement calculates the following: peak phase error rms
GSM_FRQ performs the frequency error measurement described in [1, 2]. The frequency error measurement is used to verify GMSK modulation accuracy. The GSM_PHS measurement can be used how to calculate frequency error to perform the phase error measurement that is also part of the GMSK
Phase Error Calculation
modulation accuracy measurements. Parameters Name Type Range Block Diagram System Diagram N/A GSM Vector Signal Analyzer GSM VSA deped frequency of error form Meter N/A X-Axis display List of options N/A Y-Axis display List of options N/A Display overall maximum Check box N/A Display cumulative average Check box N/A Display reference limit Check box N/A http://rfmw.em.keysight.com/rfcomms/refdocs/gsm/meas_pfer_desc.html Result This measurement returns real values. If more than one display option is checked, multiple traces are displayed, with the first trace corresponding to the top-most checked display option. The X-axis display parameter determines what is displayed for the x-axis. For the power options, the x-axis values are in the log power units (dBm or dB) specified in the project options. The Y-axis https://awrcorp.com/download/faq/english/docs/VSS_Measurements/gsm_frq.htm units are determined by the Y-Axis display parameter. If Y-Axis display is set to "ppm" and the measured signal has a carrier frequency of 0, the results are displayed in Hz. Graph Type This measurement can be displayed on a rectangular graph or tabular grid. Computational Details This measurement must be connected to a GSM_VSA meter. The measurement compares the measured signal to the generated test signal from the VSA meter in several steps: 1. The phase trajectory (phase versus time) over the useful part of each burst is calculated for both the reference and the measured signal. The useful part of the burst starts halfway through the first symbol and continues for 147 symbols. The phase trajectory is calculated using the following: φ[i] = φ[i-1]+Δθ[i]+adj[i] φ[0]=θ[0] Δθ[i]=θ[i]-θ[i-1] adj[i]=-2π if Δθ[i]>π adj[i]=2π if Δθ[i]<π adj[i]=0; otherwise The adj[i] term is used to compensate for +/- π wraparound. 2. The phase difference trajectory is calculated by subtracting the phase trajectory of the reference signal from the phase trajectory of the measured signal: φDiff[i]=φMeas[i]-φRef[i]+φAdj[i] φAdj[i]=-2π if(φMeas[i]-φRef[i])>π φAdj[i]=2π if(φMeas[i]-φRef[i])≤-π φAdj[i]=0 otherwise The φAdj[i] term is used to compensate for +/- π wraparou
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