www.gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\lpcrf2rr.m
function [rr,ar]=lpcrf2rr(rf,p); %LPCRR2AR convert reflection coefs to autocorrelation coefs [RR,AR]=(RF,P) % % Inputs: rf(:,n+1) reflection coefficients: one row per frame % p specifies number of rr coefficients to calculate (default=n) % Outputs: rr(:,p+1) autocorrelation coefficients % ar(:,n+1) AR filter coefficients % Copyright (C) Mike Brookes 1997 % % Last modified Fri May 22 07:57:50 1998 % % VOICEBOX 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 % ftp://prep.ai.mit.edu/pub/gnu/COPYING-2.0 or by writing to % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [nf,p1]=size(rf); p0=p1-1; a = rf(:,2); rr=[ones(nf,1) -a zeros(nf,p0-1)]; e = (a.^2-1); for n = 2:p0 k=rf(:,n+1); rr(:,n+1) =k.*e - sum(rr(:,n:-1:2).*a,2); a = [a+k(:,ones(1,n-1)).*a(:,n-1:-1:1) k]; e = e.*(1-k.^2); end ar = [ones(nf,1) a]; r0=sum(rr.*ar,2).^(-1); rr=rr.*r0(:,ones(1,p1)); if nargin>1 if p<p0 rr(:,p+2:p1)=[]; else rr=[rr zeros(nf,p-p0)]; af=-ar(:,p1:-1:2); for i=p0+1:p rr(:,i+1)=sum(af.*rr(:,i-p0+1:i),2); end end end