dsb.m

很好的Matlab代码 有好东西大家共同分享 适合想下载双边带调制的同志。

clear all;
clc;
t=0:1/(600*1000-1):0.01;
m1=sin(500*2*pi*t);
m2=sin(2*pi*2000*t);
m=m1+m2;
%x=m.*sin(2*pi*150*1000*t);

z=amod(m,1.5*10^5,6*10^5,'amdsb-sc')
figure(1);
subplot(2,1,1),plot(t,z);
title('DSB-SC信号图');
y=awgn(z,5);
subplot(2,1,2),plot(t,y);
title('加入噪声后的DSB-SC图，SNR=5');
figure(2);
f=(0:length(fft(z))-1)*(600*1000-1)/length(fft(z));
subplot(2,1,1);plot(f,abs(fft(z)));

%z=y.*sin(2*pi*150*1000*t);
figure(2);
f=(0:length(fft(z))-1)*(600*1000-1)/length(fft(z));
subplot(2,1,1);plot(f,abs(fft(z)));
title('调制后的频谱图');
[num,den]=butter(20,300*1000/(600*1000-1));
z1=ademod(y,150*1000,600*1000,'amdsb-sc',num,den);
f=(0:length(fft(z1))-1)*(600*1000-1)/length(fft(z1));
subplot(2,1,2);
plot(f,abs(fft(z1)));
axis([0 6000 0 3500]);
title('解调后的频谱图');