function?S=capon（xMfN）
%Capon?spectrum?estimation?
%?x?::?the?input?data?array
%?M?::?the?order?of?the?covariance?toeplitz?matrix
%?fN::?the?number?of?sampling?in?the?fequency?domain?[0?2*pi）
Lx=length（x）;
corrx=xcorr（x‘biased‘）;
corrx=corrx（Lx:Lx+M-1）;
corrxtp=toeplitz（corrx）;
clear?corrx;
corrxtpinv=inv（corrxtp）;
clear?corrxtp;
S=zeros（fN1）;
FR=fft（corrxtpinvfN1）;
%temp=corrxtpinv*corrxtpin