gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\lpcrf2la.m
function la=lpcrf2la(rf) %LPCRF2LA Convert reflection coefficients to log areas LA=(RF) % areas are normalised to give la(p+2)=0, the log area of the free space beyond lips % Copyright (C) Mike Brookes 1997 % % Last modified Tue May 12 16:18:40 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. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% r=max(min(rf,1-1E-6),1E-6-1); lo=log((1-r)./(1+r)); la=fliplr([zeros(size(rf,1),1) cumsum(fliplr(log((1-r)./(1+r))).').']);