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MATLAB数字信号调制解调仿真代码

news 2026/7/30 21:22:29

1.参数设置

% 参数设置M=4;% 调制阶数（例如，4表示4-ASK、4-PSK、4-FSK）fs=1000;% 采样频率（Hz）fc=100;% 载波频率（Hz）T=1;% 符号持续时间（秒）N=T*fs;% 每个符号的采样点数numSymbols=1000;% 符号数量EbNo=10;% 能量与噪声比（dB）

2.生成随机数据

% 生成随机数据data=randi([0,M-1],1,numSymbols);

3.调制过程

3.1 ASK调制

% ASK调制askModulated=zeros(1,numSymbols*N);fori=1:numSymbols symbol=data(i);t=(0:N-1)/fs;% 时间向量askModulated((i-1)*N+1:i*N)=symbol*cos(2*pi*fc*t);end

3.2 PSK调制

% PSK调制pskModulated=zeros(1,numSymbols*N);fori=1:numSymbols symbol=data(i);t=(0:N-1)/fs;% 时间向量pskModulated((i-1)*N+1:i*N)=cos(2*pi*fc*t+2*pi*symbol/M);end

3.3 FSK调制

% FSK调制fskModulated=zeros(1,numSymbols*N);fori=1:numSymbols symbol=data(i);t=(0:N-1)/fs;% 时间向量fskModulated((i-1)*N+1:i*N)=cos(2*pi*(fc+symbol*fc/M)*t);end

4.信道模型（加性高斯白噪声）

% 信道模型（AWGN）noise=(randn(1,numSymbols*N)+1j*randn(1,numSymbols*N))/sqrt(2)*10^(-EbNo/20);askReceived=askModulated+noise;pskReceived=pskModulated+noise;fskReceived=fskModulated+noise;

5.解调过程

5.1 ASK解调

% ASK解调askDemodulated=zeros(1,numSymbols);fori=1:numSymbols receivedSignal=askReceived((i-1)*N+1:i*N);askDemodulated(i)=round(abs(mean(receivedSignal)));end

5.2 PSK解调

% PSK解调pskDemodulated=zeros(1,numSymbols);fori=1:numSymbols receivedSignal=pskReceived((i-1)*N+1:i*N);angle=angle(mean(receivedSignal));pskDemodulated(i)=round(angle/(2*pi/M));end

5.3 FSK解调

% FSK解调fskDemodulated=zeros(1,numSymbols);fori=1:numSymbols receivedSignal=fskReceived((i-1)*N+1:i*N);fskDemodulated(i)=round((mean(receivedSignal)-fc)/(fc/M));end

6.误码率计算

% 误码率计算BER_ask=sum(abs(data-askDemodulated))/numSymbols;BER_psk=sum(abs(data-pskDemodulated))/numSymbols;BER_fsk=sum(abs(data-fskDemodulated))/numSymbols;fprintf('ASK误码率 (BER): %.4f\n',BER_ask);fprintf('PSK误码率 (BER): %.4f\n',BER_psk);fprintf('FSK误码率 (BER): %.4f\n',BER_fsk);

7.绘图

% 绘制调制信号t=(0:numSymbols*N-1)/fs;figure;subplot(3,1,1);plot(t,askModulated);title('ASK调制信号');xlabel('时间 (s)');ylabel('振幅');subplot(3,1,2);plot(t,pskModulated);title('PSK调制信号');xlabel('时间 (s)');ylabel('振幅');subplot(3,1,3);plot(t,fskModulated);title('FSK调制信号');xlabel('时间 (s)');ylabel('振幅');