www.pudn.com > voicebox2.zip > LPCAR2RA.M

function ra=lpcar2ra(ar) 
%LPCAR2RA Convert ar filter to inverse filter autocorrelation coefs. RA=(AR) 
 
 
%      Copyright (C) Mike Brookes 1997 
% 
%      Last modified Tue Dec 28 22:53:36 1999 
% 
%   VOICEBOX is a MATLAB toolbox for speech processing. Home page is at 
%   http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 
% 
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%   This program is free software; you can redistribute it and/or modify 
%   it under the terms of the GNU General Public License as published by 
%   the Free Software Foundation; either version 2 of the License, or 
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%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
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%   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 
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[nf,p1]=size(ar); 
ra=zeros(nf,p1); 
for i=1:p1 
   ra(:,i)=sum(ar(:,1:p1+1-i).*ar(:,i:p1),2); 
end