基于matlab的通信系统仿真程序和simulink框图精选.doc

程序： clear all clear all clc a=30; source=zeros(1,a); source=randint(1,a,2); %产生长度为a的随机二进制信号 figure(1);subplot(3,2,1);stem(source);title(二进制信号波形);grid on; axis([0,a, -0.1,1.1]); x=source; %%%%%%%%%%%%%%差分编码%%%%%%%%%%%%%%%%% y1=zeros(1,a); for n=1:a-1 y1(n)=xor(x(n),x(n+1)) end figure(1);subplot(3,2,2);stem(y1);title(差分编码后信号波形);grid on; axis([0,a, -0.1,1.1]); %%%%%%%%%%%%%%%BPSK调制%%%%%%%%%%%%%%% fc=4800; %fd=2400; %码元速率 fs=12000; %采样频率 y2=dmod(x,fc,fd,fs,psk,2); figure(1);subplot(3,2,3);plot(y2);title(BPSK调制后信号波形);grid on; axis([0,a,-1.1,1.1]); %%%%%%%%%%%%%%加入带有高斯白噪声的信道%%%%%%%%%%% b=3 y3=awgn(y2,b);%信号调制中加入白噪声，信噪比为b figure(1);subplot(3,2,4);plot(y3);title(经过高斯白噪声信道后的信号);grid on; axis([0,a, -1.1,1.1]); %%%%%%%%%%%%%%%%%%BPSK解调%%%%%%%%%%%%%%%% fc=4800; fd=2400; fs=12000; y4=ddemod(y3,fc,fd,fs,psk,2); figure(1);subplot(3,2,5);stem(y4);title(BPSK解调后信号波形);grid on; axis([0,a,-0.1,1.1]); %%%%%%%%%%%%%%差分译码%%%%%%%%%%%%%%%%% k=ones(1,a+1) for n=1:a k(n+1)=y4(n); end y5=zeros(1,a+1); y5(1)=1; for n=1:a y5(n+1)=xor(k(n+1),y5(n)); end figure(1);subplot(3,2,6);stem(y5);title(差分译码后信号波形);grid on; axis([0,a,-0.1,1.1]); %%%%%%%%%%%%%%%%误码率曲线%%%%%%%%%%%%%% figure(2) r=-6:3:24;%信噪比范围 rr=10.^(r/10);%误码率公式 pe1=1/2*exp(-rr);%相干解调的误码率曲线 hold on plot(r,pe1,r);title(误码率曲线);grid on; Simulink仿真基本通信系统框图如下：