LPCRR2AR convert autocorrelation coefs to ar coefs [AR,E]=(RR) E is the residual energy

0001 function [ar,e]=lpcrr2ar(rr); 0002 %LPCRR2AR convert autocorrelation coefs to ar coefs [AR,E]=(RR) 0003 %E is the residual energy 0004 0005 % could test e each time and remove rows when it gets small 0006 0007 0008 % Copyright (C) Mike Brookes 1997 0009 % Version: $Id: lpcrr2ar.m 713 2011-10-16 14:45:43Z dmb $ 0010 % 0011 % VOICEBOX is a MATLAB toolbox for speech processing. 0012 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0013 % 0014 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0015 % This program is free software; you can redistribute it and/or modify 0016 % it under the terms of the GNU General Public License as published by 0017 % the Free Software Foundation; either version 2 of the License, or 0018 % (at your option) any later version. 0019 % 0020 % This program is distributed in the hope that it will be useful, 0021 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0022 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0023 % GNU General Public License for more details. 0024 % 0025 % You can obtain a copy of the GNU General Public License from 0026 % http://www.gnu.org/copyleft/gpl.html or by writing to 0027 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0028 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0029 0030 [nf,p1]=size(rr); 0031 p=p1-1; 0032 ar=ones(nf,p1); 0033 ar(:,2) = -rr(:,2)./rr(:,1); 0034 e = rr(:,1).*(ar(:,2).^2-1); 0035 for n = 2:p 0036 k = (rr(:,n+1)+sum(rr(:,n:-1:2).*ar(:,2:n),2)) ./ e; 0037 ar(:,2:n) = ar(:,2:n)+k(:,ones(1,n-1)).*ar(:,n:-1:2); 0038 ar(:,n+1) = k; 0039 e = e.*(1-k.^2); 0040 end 0041 e=-e;

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