shifen.m

实现了时分复用,并在信道中加入高斯白噪声

%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%两路正弦信号的时分复用%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%

fs=10000;
t=0:1/fs:0.1;
f1=50;
f2=100;
x1=sin(2*pi*f1*t);
x2=sin(2*pi*f2*t);
y=[x1(1) x2(1)];
for k=2:1001
    y=[y x1(k) x2(k)];
end
figure(1);
subplot(2,1,1);plot(t,x1); 
xlabel('sec');ylabel('x1');title('原始信号1');
subplot(2,1,2);plot(t,x2);
xlabel('sec');ylabel('x2');title('原始信号2');


figure(3);
subplot(2,1,1);plot(t,y(1:1001));title('传输信号');
                 
                              
T=0:1/(2*fs):0.1;
r1=y(1);
for k=2:1001
    r1=[r1 y(2*k-1)];
end

r2=y(2);
for k=2:1001
    r2=[r2 y(2*k)];
end
figure(4);
subplot(4,1,1);plot(t,r1);title('接收到的原始信号1');
subplot(4,1,2);plot(t,r2);title('接收到的原始信号2');


%加入噪声
SNRpBit=20;                                    %信噪比
M=2;                                           %进制数
SNR=SNRpBit/log2(M);
y=awgn(y,SNR,'measured',[],'dB');              %在已调信号中加入高斯白噪声
figure(3);
subplot(2,1,2);plot(t,y(1:1001));
xlabel('sec');ylabel('y');title('加入噪声后的传输信号')

r1=y(1);
for k=2:1001
    r1=[r1 y(2*k-1)];
end
    r2=y(2);
for k=2:1001
    r2=[r2 y(2*k)];
end
figure(4);
subplot(4,1,3);plot(t,r1);axis([0 0.1 -1 1]);title('加噪后接收到的原始信号1');
subplot(4,1,4);plot(t,r2);axis([0 0.1 -1 1]);title('加噪后接收到的原始信号2');