www.gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\lpcra2pf.m
function pf=lpcra2pf(ra,np) %LPCAR2PF Convert AR coefs to power spectrum PF=(RA,NP) % The routine is faster if NP+1 is a power of 2 % For RA(:,p+1) the default value of np is p and the output is PF(:,p+2) % Copyright (C) Mike Brookes 1997 % % Last modified Wed Dec 29 15:22:14 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 % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 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(ra); if nargin<2 np=p1-1; end pp=2*np+2; if pp>=2*p1 pf=abs(rfft([ra zeros(nf,pp-2*p1+1) ra(:,p1:-1:2)].').').^(-1); else pf=abs(rfft([ra(:,1:np+2) ra(:,np+1:-1:2)].').').^(-1); end