lpccc2ar.m

this is speech recognition file

function ar=lpccc2ar(cc)
%LPCCC2AR Convert complex cepstrum to ar coefficients AR=(CC)
%
% MATLAB5 version


%      Copyright (C) Mike Brookes 1998
%      Version: $Id: lpccc2ar.m,v 1.4 2007/05/04 07:01:38 dmb Exp $
%
%   VOICEBOX is a MATLAB toolbox for speech processing.
%   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   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
%   (at your option) any later version.
%
%   This program is distributed in the hope that it will be useful,
%   but WITHOUT ANY WARRANTY; without even the implied warranty of
%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%   GNU General Public License for more details.
%
%   You can obtain a copy of the GNU General Public License from
%   http://www.gnu.org/copyleft/gpl.html or by writing to
%   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

[nf,p]=size(cc);
rp=-(1:p);
cc = cc .* rp(ones(nf,1),:);
if p<2
  ar = [ones(nf,1) cc(:,1)];
else
 ar=zeros(nf,p+1);
 ar(:,1:3) = [ones(nf,1) cc(:,1) (cc(:,2)+cc(:,1).^2)/2];
  for k=3:p
    ar(:,k+1) = (cc(:,k) + sum(cc(:,1:k-1).*ar(:,k:-1:2),2))/k;
  end
end