SSB(滤波法法)调制解调Matlab.m文件源码

xlabel('f');title('调制信号频谱');

axis([-fc-5*f0,fc+5*f0,0,max(M)+0.3]);

set(gca,'XTick', -10:10:10);

set(gca,'XGrid','on');

%%

%载波及其频谱

subplot(413);

c = cos(2*pi*fc*t); %载波

plot(t,c);

axis([0,t0,-E-0.2,E+0.2]);

xlabel('t');title('载波');

subplot(414); %载波频谱

[C,c,df1,f] = T2F_new(c,dt,df,fs);

plot(f,fftshift(abs(C))); %画出载波频谱

xlabel('f');title('载波频谱');

axis([-fc-5*f0,fc+5*f0,0,max(C)+0.3]);

set(gca,'XTick', -10:10:10);

set(gca,'XGrid','on');

%%

%已调信号及其频谱

figure(2);

subplot(321); %画已调信号

u = m(1:Lt).*c(1:Lt);

plot(t,u);

axis([0,t0,-max(u)-0.5,max(u)+0.5]);

xlabel('t');title('DSB信号');

set(gca,'YTick', -max(u):1:max(u));

subplot(322);

[U,u,df1,f] = T2F_new(u,dt,df,fs);

plot(f,fftshift(abs(U))); %画出已调信号频谱

xlabel('f');title('DSB信号频谱');

axis([-fc-5*f0,fc+5*f0,0,max(U)+0.3]);

set(gca,'XTick', -10:10:10);

set(gca,'XGrid','on');

%%

%滤波法产生SSB信号

[H_low,f_low] = bp_f(length(u),f_start_low,f_cutoff_low,df1,fs,1);%求滤波法产生下边带需要的带通滤波器

[H_high,f_high] = bp_f(length(u),f_start_high,f_cutoff_high,df1,fs,1);