function Px = minvar(x,p)%MINVAR	Spectrum estimation using the minimum variance method.%----%USAGE	Px = minvar(x,p) %%	The spectrum of a process x is estimated using the minimum%	variance method (sometimes called the maximum likelihood%	method).%%	x  :  Input sequence%	p  :  Order of the minimum variance estimate - for short%		sequences, p is typically about length(x)/3%%	The spectrum estimate is returned in Px using a dB scale.%%---------------------------------------------------------------% copyright 1996, by M.H. Hayes.  For use with the book % "Statistical Digital Signal Processing and Modeling"% (John Wiley & Sons, 1996).%---------------------------------------------------------------%   x = x(:);   R = covar(x,p);   [v,d]=eig(R);   U = diag(inv(abs(d)+eps));   V  = abs(fft(v,1024)).^2;   Px = 10*log10(p)-10*log10(V*U);   end;