基于matlab的通信系统仿真程序和simulink框图

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; %载频

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：