dedsbam.asv

这是关于数字通信的一些程序,希望对大家有所帮助

t0=0.15;
ts=0.001;
fc=250;
snr=20;
fs=1/ts;
df=0.3;
t=[0:ts:t0];
snr_lin=10^(snr/10);
m=[ones(1,t0/(3*ts)),-2*ones(1,t0/(3*ts)),zeros(1,t0/(3*ts)+1)];
c=cos(2*pi*fc.*t);
u=m.*c;
y=u.*c;
[M,m,df1]=fftseq(m,ts,df);
M=M/fs;
[U,u,df1]=fftseq(u,ts,df);
U=U/fs;
[Y,y,df1]=fftseq(y,ts,df);
Y=Y/fs;
f_cutoff=150;
n_cutoff=floor(150/df1);
f=[0:df1:df1*(length(y)-1)]-fs/2;
H=zeros(size(f));
H(1:n_cutoff)=2*ones(1,n_cutoff);
H(length(f)-n_cutoff+1:length(f))=2*ones(1,n_cutoff);
DEM=H.*Y;
dem=real(ifft(DEM))*fs;

figure
plot(f,(1:length(f)))
figure
plot(t,u(1:length(t)))
figure
plot(t,dem(1:length(t)))