matlab.rar_GSM_GSM 解调_gsm 解调_gsm demodulation_gsm edge

function pskevm() Tnormal = 6/1625000; % Normal symbol duration in seconds M = 8; % Modulation order (8-PSK) burstLen1 = 174+78+174; % Number of symbols in the % useful part of the burst burstLen2 = burstLen1+9; % Number of symbols in the burst numBursts = 200; % Number of bursts Nsamp = 4; % Number of samples that represents a symbol Fs = Nsamp/Tnormal; % Final sampling rate SNR = 60; % Simulated signal-to-noise ratio in dB % Create a 8-PSK comm.PSKModulator System object with 0 Phase Offset and % user-defined symbol mapping. hMod = comm.PSKModulator(8, 'PhaseOffset', 0, 'SymbolMapping', 'Custom'); hMod.CustomSymbolMapping = [7 3 2 0 1 5 4 6]; % Calculate the phase rotation vector phaseRotation1 = exp(1i*(0:burstLen2-1)'*3*pi/8); phaseRotation2 = exp(1i*(0:burstLen1-1)'*3*pi/8); % Create a linearized GMSK pulse shaping filter c0 = commEDGE_getLinearizedGMSKPulse(Nsamp); hLinGMSK = dfilt.dffir(c0/max(c0)); % Create an comm.AWGNChannel System object. Set the NoiseMethod property of % the channel to 'Signal to noise ratio (SNR)'. hChan = comm.AWGNChannel('NoiseMethod', 'Signal to noise ratio (SNR)',... 'SNR', SNR); % Since the AWGN Channel system object as well as the RANDI function use % the default random stream, the following commands are executed so that % the results will be repeatable, i.e. same results will be obtained for % every run of the demo. The default stream will be restored at the end of % the demo. s = RandStream.create('mt19937ar', 'seed',55408); prevStream = RandStream.setGlobalStream(s); % Design a raised cosine filter with roll off factor 0.25 Nsym = 8; % Filter order in symbols beta = 0.25; % Roll-off factor measFiltDef = fdesign.pulseshaping(Nsamp, 'Raised Cosine', ... 'Nsym,Beta', Nsym, beta, Nsamp/Tnormal); hMeasFilt = design(measFiltDef); % Apply the window and normalize the filter gain w = commEDGE_getRaisedCosineWindow(Nsamp); hMeasFilt.Numerator = hMeasFilt.Numerator.*w; hEVM = comm.EVM('Normalization', 'Average reference signal power', ... 'MaximumEVMOutputPort', true, 'XPercentileEVMOutputPort',true) % Calculate delays refSigDelay = (length(hLinGMSK.Numerator) - 1) / 2; delayXUptoS = (length(hMeasFilt.Numerator) - 1)/2; rcvSigDelay = refSigDelay + delayXUptoS; % Initialize total peak EVM totalMaxEVM = 0; maxRMSEVM = 0; % Loop over bursts for p=1:numBursts % Generate random data d = randi([0 M-1], burstLen2, 1); % Modulate x = step(hMod, d); % Rotate phase x = x .* phaseRotation1; % Pulse shape xUp = filter(hLinGMSK, upsample(x, Nsamp)); % Calculate input signal power and set the 'SignalPower' property % of the AWGNChannel object hChan.SignalPower = (xUp' * xUp)/ length(xUp); % Add noise r = step(hChan, xUp); % Pass through the measurement filter s = filter(hMeasFilt, r); % Downsample both received and reference signals. % Account for the filter delays sd = s(rcvSigDelay+1:Nsamp:end); xd = xUp(refSigDelay+1:Nsamp:end); % Reset EVM object reset(hEVM) % Measure using the EVM system object [rmsEVM,MaxEVM,PercentileEVM] = step(hEVM,(sd(1:burstLen1)), ... (xd(1:burstLen1))); % Update maximum RMS EVM maxRMSEVM = max([maxRMSEVM rmsEVM]); % Update maximum EVM sum totalMaxEVM = totalMaxEVM + MaxEVM; end % Calculate peak EVM peakEVM = totalMaxEVM / numBursts; % Display results fprintf(' Worst case RMS EVM (%%): %f\n', maxRMSEVM) fprintf(' Peak EVM (%%): %f\n', peakEVM) fprintf('95th percentile EVM (%%): %f\n', PercentileEVM) % Restore default stream RandStream.setGlobalStream(prevStream);