Bpsk Matlab Code

VOICE BASEBAND MODEM %BPSK_sim.m BPSK modulation and demodulation of a random bit stream clear; close all SNR = 0.5; %Signal to noise ratio E_s = 1; %Signal Power No = E_s^2/SNR; %Noise Power sig_n = sqrt(No/2); %Noise standard deviation w=2*pi*5; %Frequency t=0.01:0.01:0.2; %Time Vector N=200; %Number of Bits %Create Signal Vectors for ii=1:2 s(ii,:) = E_s*cos(w*t-2*pi*ii/2); end %Modulate a random bit stream signal = ceil(2*rand(1,N)); m_sig = []; for ii=1:N m_sig = [m_sig s(signal(ii),:)]; end plot(m_sig(1:100),':') %plot the transmitted signal n = sig_n*randn(1,length(m_sig)); %Create a noise vector r = m_sig + n; %Received Signal = s + n hold on; plot(r(1:100),'r') %Plot the received signal title('Transmitted and Received signals') legend('Transmitted Waveform', 'Received Waveform') sigma1 = E_s*cos(w*t); %Create basis functions sigma2 = E_s*sin(w*t); index = 1:length(t); for ii=0:N-1 %detect the signal X(ii+1) = sum(sigma1.*r(ii*length(t) + index)); Y(ii+1) = sum(sigma2.*r(ii*length(t) + index)); end currFig = figure; %double buffer so window set(currFig,'DoubleBuffer','on'); %does not flash title('Detections and decision regions') %Plot the detections hold on; axlim = 30; axis([-axlim axlim -axlim, axlim]) plot([0 0],[-axlim axlim], 'k') for ii=1:N %Make decisions on received bits if(X(ii) < 0) received_sig(ii) = 1; else received_sig(ii) = 2; end figure(currFig) if and(received_sig(ii)-signal(ii),1) plot(X(ii),Y(ii),'ro') else plot(X(ii),Y(ii),'bx')

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Transcript of Bpsk Matlab Code

VOICE BASEBAND MODEM

%BPSK_sim.m BPSK modulation and demodulation of a random bit streamclear; close allSNR = 0.5; %Signal to noise ratioE_s = 1; %Signal PowerNo = E_s^2/SNR; %Noise Powersig_n = sqrt(No/2); %Noise standard deviationw=2*pi*5; %Frequencyt=0.01:0.01:0.2; %Time VectorN=200; %Number of Bits%Create Signal Vectorsfor ii=1:2 s(ii,:) = E_s*cos(w*t-2*pi*ii/2);end%Modulate a random bit streamsignal = ceil(2*rand(1,N));m_sig = [];for ii=1:N m_sig = [m_sig s(signal(ii),:)];endplot(m_sig(1:100),':') %plot the transmitted signaln = sig_n*randn(1,length(m_sig)); %Create a noise vectorr = m_sig + n; %Received Signal = s + nhold on; plot(r(1:100),'r') %Plot the received signaltitle('Transmitted and Received signals')legend('Transmitted Waveform', 'Received Waveform')sigma1 = E_s*cos(w*t); %Create basis functionssigma2 = E_s*sin(w*t);index = 1:length(t);for ii=0:N-1 %detect the signal X(ii+1) = sum(sigma1.*r(ii*length(t) + index)); Y(ii+1) = sum(sigma2.*r(ii*length(t) + index));end currFig = figure; %double buffer so windowset(currFig,'DoubleBuffer','on'); %does not flashtitle('Detections and decision regions') %Plot the detectionshold on;axlim = 30;axis([-axlim axlim -axlim, axlim])plot([0 0],[-axlim axlim], 'k')

for ii=1:N %Make decisions on received bits if(X(ii) < 0) received_sig(ii) = 1; else received_sig(ii) = 2; end figure(currFig) if and(received_sig(ii)-signal(ii),1) plot(X(ii),Y(ii),'ro') else plot(X(ii),Y(ii),'bx') end hold on pause(0.1)endx=received_sig - signal;n_errors = sum(and(x,1)) p_error = n_errors / N %Calculate the percentage errorwavwrite(m_sig,5500,16,'bpsk.wav') %write the wav fileswavwrite(r,5500,16,'bpsk_n.wav')