nonlinerls.m

恒模信号估计。估计载波的频率和振幅。估计恒模信号的相位和振幅

clear
clc
close all
load c2.mat;
c2 = hilbert(c2);
% clear c1dw
t0 = 10;
% clear a1 c1
fs = 2*10^5;
N = t0*fs;

%估计载波的频率和振幅
omega_0 = fminbnd(@(omega)-abs((c2(1:N)*(exp(j*omega*[1:N]))'))^2,45000,55000);
%  afi_0=abs(c2(1:1000)*eye(1000,1000)*(-(exp(j*omega_0*[1:1000]))'))/1000
 afi_0=0;
for i=1:N
   afi_0=afi_0+abs(c2(i)*exp(-j*omega_0*i));
end
afi_0=afi_0/N;
%估计恒模信号的相位和振幅
fi=zeros(1,N);
y=zeros(1,N);
y=c2(1:N)-afi_0*exp(j*omega_0*[1:N]);
fi=angle(y);
afi=0;
for i=1:N
 afi=afi+abs(y(i));
end
afi=afi/N;

for k=1:100
%%估计载波的频率和振幅
y_0=c2(1:N)-afi*exp(j*fi);
omega_0 = fminbnd(@(omega)-abs((y_0(1:N)*(exp(j*omega*[1:N]))'))^2,45000,55000);
for i=1:N
   afi_0=afi_0+abs(c2(i)*exp(-j*omega_0*i));
end
afi_0=afi_0/N;

%估计恒模信号的相位和振幅
y_1=c2(1:N)-afi_0*exp(-j*omega_0*[1:N]);
fi=zeros(1,N);
y=zeros(1,N);
y=c2(1:N)-afi_0*exp(j*omega_0*[1:N]);
fi=angle(y);
afi=0;
for i=1:N
 afi=afi+abs(y(i));
end
afi=afi/N;
end

%%%% 解调
dem1 = real(y_1).*real(afi_0*exp(-j*omega_0*[1:N]));
n = 128;                                    
wn = [ 0.1 ];                             
b = fir1( n, wn );
a = 1;
dem1 = filter( b, a, dem1 );                 % fs = 2*10^5
dem1 = dem1 - mean( dem1 );
dem2=dem1(1:4:end);              
dem1 = dem1 / max(dem1);