deam.m

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;
a=0.85;
fs=1/ts;
df=0.25;
t=[0:ts:t0];
m=[ones(1,t0/(3*ts)),-2*ones(1,t0/(3*ts)),zeros(1,t0/(3*ts)+1)];
c=cos(2*pi*fc.*t);
m_n=m/max(abs(m));
[M,m,df1]=fftseq(m,ts,df);
M=M/fs;
f=[0:df1:df1*(length(m)-1)]-fs/2;
u=(1+a*m_n).*c;
[U,u,df1]=fftseq(u,ts,df);
U=U/fs;
env=env_phas(u);
dem1=2*(env-1)/a;
signal_power=spower(u(length(t)));
noise_power=signal_power/100;
noise_std=sqrt(noise_power);
noise=noise_std*randn(1,length(u));
r=u+noise;
[R,r,df1]=fftseq(r,ts,df);
R=R/fs;
env_r=env_phas(r);
dem2=2*(env_r-1)/a;
subplot(2,1,1);
plot(t,env_r(1:length(t)))