SSB(滤波法法)调制解调Matlab.m文件源码

subplot(321); %经过理想带通滤波器后的信号波形

plot(t,dem(1:Lt)); %画出经过理想带通滤波器后的信号波形

axis([0,t0,-max(dem)-0.3,max(dem)+0.3]);

xlabel('t');title('理想BPF输出信号');

%%

[demf,dem,df1,f] = T2F_new(dem(1:Lt),dt,df,fs);%求经过理想带通滤波器后的信号频谱 subplot(322);

plot(f,fftshift(abs(demf))); %画出经过理想带通滤波器后信号频谱 xlabel('f');title('理想BPF输出信号频谱');

axis([-fc-5*f0,fc+5*f0,0,max(demf)+0.1]);

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

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

%%

%--------------和本地载波相乘，即混频

subplot(323);

plot(t,c(1:Lt));

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

xlabel('t');title('本地载波');

subplot(324); %频谱载波

[C,c,df1,f] = T2F_new(c(1:Lt),dt,df,fs);

plot(f,fftshift(abs(C))); %画出载波频谱

xlabel('f');title('本地载波频谱');

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

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

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

%再画出混频后信号及其频谱

der = dem(1:Lt).*c(1:Lt); %混频

%%

subplot(325); %画出混频后的信号

plot(t,der);

axis([0,t0,-R,R]);

xlabel('t');title('混频后的信号');

subplot(326);

[derf,der,df1,f] = T2F_new(der,dt,df,fs); %求出混频后的信号频谱

plot(f,fftshift(abs(derf))); %画出混频后的信号频谱

xlabel('f');title('混频后的信号频谱');

axis([-2*fc-5*f0,2*fc+5*f0,0,max(derf)+0.3]);