双二进制编码(Duobinary coding)MATLAB程序

clear clc close all BitStreamLength = 10^6; BitStream = rand(1, BitStreamLength) > 0.5; %将bit流分成两串 [BitStreamOne, BitStreamTwo ] = SerialToParallel( BitStream); %QPSK映射编码 [I_SymbolsTx, Q_SymbolsTx] = QPSKEncoder(BitStreamOne, BitStreamTwo); %得到QPSK信号 QPSKsig = I_SymbolsTx+1i*Q_SymbolsTx; %能量进行归一化 QPSKsig = QPSKsig./sqrt(2); %通过AWGN信道 ReceivedQPSKsig = awgn(QPSKsig,20); % 4QAM figure(1) plot(ReceivedQPSKsig,'.'); xlabel('In-Phase');ylabel('Quadrature'); axis([-1 1 -1 1]); %% QDB QDBBitStreamOne = QDBEncoder(BitStreamOne); QDBBitStreamTwo = QDBEncoder(BitStreamTwo); QDBBitStream = ParallelToStream(QDBBitStreamOne,QDBBitStreamTwo); %得到9QAM信号 QAM9sig = QDBBitStreamOne+1i*QDBBitStreamTwo; %能量进行归一化 QAM9sig = QAM9sig./sqrt(8); %通过AWGN信道 ReceivedQAM9sig = awgn(QAM9sig,20); %9QAM figure(2) plot(ReceivedQAM9sig,'.','Color','r'); xlabel('In-Phase');ylabel('Quadrature'); axis([-1 1 -1 1]); RealRecoveredSig= real(ReceivedQAM9sig); ImagRecoveredSig = imag(ReceivedQAM9sig); [RealRxQDB,ImagRxQDB,] = QAM9Decoder(RealRecoveredSig,ImagRecoveredSig); RXQDB = ParallelToStream(RealRxQDB,ImagRxQDB); % QDB译码 RecoveryBits = QDBDecoder(RXQDB); ErrorNum = size(find(BitStream-RecoveryBits),2); BER = ErrorNum/length(RecoveryBits); % %% 频谱图 % F_QAM9sig = fftshift(fft(QAM9sig./length(QAM9sig))); % FSingle_QAM9sig = F_QAM9sig(1:length(QAM9sig)/2); % figure(3) % plot(1:length(F_QAM9sig), 20*log10(abs(F_QAM9sig)),'Color','r');grid on; %% CAP信号的频谱图 F_QAM9sig = fft(QAM9sig./length(QAM9sig)); FSingle_QAM9sig = F_QAM9sig(1:length(QAM9sig)/2); Tsamping = 1/100; %微秒 SamplingNum = length(F_QAM9sig); for i = 1:length(FSingle_QAM9sig) F_xlabel(i) = (i-1)/(SamplingNum*Tsamping); end figure(5) plot(F_xlabel, 20*log10(abs(FSingle_QAM9sig)),'r');grid on; % title('The spectra of CAP-4 signal'); % xlim([0 50]);ylim([-53 -50]); xlabel('Frequency(MHz)');ylabel('Amplitude(dB)'); % F_QPSKsig = fft(QPSKsig./length(QPSKsig)); % FSingle_QPSKsig = F_QPSKsig(1:length(F_QPSKsig)/2); % figure(4) % plot(1:length(FSingle_QPSKsig), 20*log10(abs(FSingle_QPSKsig)));grid on;