%%%%%%%%%%%%%%%%%%%%%%%%%%%%%模擬載波雙邊帶調(diào)制fs=100;ts=1/fs;t=[0:ts:2]N=length(t)-1;df=fs/N;x=cos(10*2*pi*t);y=cos(2*pi*t);for i=1:N+1    z(i)=x(i)*y(i);endsubplot(4,1,1)plot(t,y)title('我的方法')subplot(4,1,2)plot(t,x)subplot(4,1,3)plot(t,z)%求頻譜[M,m,df1]=fftseq(z,ts,df);f=[0:df1:df1*(length(m)-1)]-fs/2;subplot(4,1,4)%stem(f,fftshift(abs(M)))%散點(diǎn)圖plot(f,fftshift(abs(M)))figure%%%%%%%%%%%%%%%%%%%%5%%%%%%%%%%%%%%%%%%%%%%%書本上的方法t=[0:2*fs+1]/fs;fc=10;x=cos(2*pi*t);ydouble=amod(x,fc,fs,'amdsb-sc');ysingle=amod(x,fc,fs,'amssb');%做出頻譜圖zdouble=fft(ydouble);zdouble=abs(zdouble(1:length(zdouble)/2+1));frqdouble=[0:length(zdouble)-1]*fs/length(zdouble)/2;subplot(4,1,1)plot(t,x)title('書本上的方法')subplot(4,1,2)plot(t,cos(fc*2*pi*t))subplot(4,1,3)plot(t,ydouble)subplot(4,1,4)plot(frqdouble,zdouble);