function R=covar(x,p)
%COVAR	Generates a covariance matrix/
%-----
%USAGE	R=covar(x,p)
%
%	Generates a p x p covariance matrix for the sequence x.
%
%---------------------------------------------------------------
% copyright 1996, by M.H. Hayes.  For use with the book 
% "Statistical Digital Signal Processing and Modeling"
% (John Wiley & Sons, 1996).
%---------------------------------------------------------------

x = x(:);
   m = length(x);
   x = x - ones(m,1)*(sum(x)/m);
   R = convm(x,p)'*convm(x,p)/(m-1);
   end;