function Px = mem(x,p)
%MEM	Spectrum estimation using the Maximum Entropy Method (MEM).
%---
%USAGE	Px = mem(x,p) 
%
%	The spectrum of a process x is estimated using the maximum
%	entropy method, which uses the autocorrelation method to 
%	find a pth-order all-pole model for x(n), and then forms 
%	the estimate of the spectrum as follows:
%		Px = b^2(0)/|A(omega)|^2 
%	The spectrum estimate is returned in Px using a dB scale.
%          x  :  Input sequence
%          p  :  Order of the all-pole model
%
%---------------------------------------------------------------
% copyright 1996, by M.H. Hayes.  For use with the book 
% "Statistical Digital Signal Processing and Modeling"
% (John Wiley & Sons, 1996).
%---------------------------------------------------------------

[a,e] = acm(x,p);
   Px = 10*log10(e/length(x))-20*log10(abs(fft(a,1024)));
end;