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From: alex65111 on 3 May 2010 17:05
I try to understand such questions as cyclostatoionarity and spectral
correlation.
As an example I used a code
http://www.mathworks.de/matlabcentral/fx_files/16742/1/freqsymrate.m

But when I create the signal of type PSK and I apply a part of code
CYCLOSTATOIONARITY BASED FREQUENCY ESITMATION on an output of procedure in
any way it is not possible to receive spectral lines connected with symbol
rate and carrier frequency.

Question - where a mistake?



clear all
clc; close all; clear all; warning('off');
M1 = 2; % Alphabet size
K=50*4*1;

%-------------------------------------------------
x1 = randint(K,1,M1); % Message signal
y1 = qammod(x1,M1);
ynoisy1=y1;
ynoisy1=resample(ynoisy1,4,1);
f1=0.0;
t1=0:(length(ynoisy1)-1);
s1=exp(sqrt(-1)*2*pi*f1*t1);
s=s1.*ynoisy1';
%------------------------------------------------
Carrier = awgn(s,10,'measured');


% CYCLOSTATOIONARITY BASED FREQUENCY ESITMATION.
Fs=100;
f=Fs/2;

len = length(Carrier);
shfT = 1/Fs:1/Fs:((len*(1/Fs)));


Fup = 2*f;
Fdwn = -Fup;
resol = 0.005;
Delf = Fdwn;

for ii = 1:1:((2*Fup)/resol)

XT = Carrier.*exp(j*2*pi*Delf*shfT);
XY = xcorr(Carrier,XT);
YT = fft(XY).*conj(fft(XY));
pt(ii) = sum((YT));
Delf = Delf + resol;

end

Fscal = Fdwn:resol:Fup;
figure; plot(Fscal(1,(1:end-1)),(pt));

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