matlab - error with cyclic autocorrelation function -

i'm trying code cyclic autocorrelation function in matlab follows:

t=0:(n-1); t=t*te; i_alpha=0; tau=-n2*te:te:n2*te; alpha=-1/2:1/n:1/2; ryy_cl=zeros(length(alpha),length(tau)); alpha=alpha/te     ind_tau=0;     i_alpha=i_alpha+1;     k=tau         ind_tau=ind_tau+1;      if k>0  %             ryy_cl(i_alpha,ind_tau)=1/length(sig_bin_syl_mod(1:end-   k))*sum((sig_bin_syl_mod(1:end-k)).*sig_bin_syl_mod(k+1:end)).*exp(1i*2*pi*alpha*t(1+k:length(sig_bin_syl_mod(1:end))));               ryy_cl(i_alpha,ind_tau)=(1/n)*sum((sig_bin_syl_mod(1:end-k)).*sig_bin_syl_mod(k+1:end)).*exp(-1i*2*pi*alpha*t(1:end-k));          else            ryy_cl(i_alpha,ind_tau)=(1/n)*sum((sig_bin_syl_mod(1-k:end)).*sig_bin_syl_mod(1:end+k)).*exp(-1i*2*pi*alpha*t(1-k:end));        end      end end 

i'm getting errors, , doesn't show expecting. according below formulae, how can fix it?

the code provided incomplete, difficult confidently reproduce error. in particular, haven't defined signal (sig_bin_syl_mod), sampling increment (te), or signal length (n).

i different errors depending on how choose te. simplest thing choose te = 1. isn't realistic. 1-mhz sampling rate have te = 1.0e-6.

when te not integer, can see 1 problem tau not integer, yet assigning k tau, using k index.

so code has basic problems.

now i'm going answer question directly. rewrite code, breaking product above separate steps can debug more easily.

first, don't try ca tau , alpha in 1 shot. focus on getting function correct single cycle frequency alpha , tau. i've put quite few helpful posts on how on cyclostationary.wordpress.com.

second, put corrected single-alpha code in loop. try make efficient.

by way, efficient alternate way estimate cyclic autocorrelation first construct cyclic periodogram (see website) , inverse fourier transform it. harnesses power of fft.

finally, link quora discusses different "cyclic autocorrelation". trying cyclostationary signal processing, link deals dft/fft , circular shifts thereof. see website definition , properties of cyclic autocorrelation of interest you.

chad