www.pudn.com > voicebox2.zip > CEP2POW.M

function [m,c]=cep2pow(u,v,mode) 
%CEP2POW convert cepstral means and variances to the power domain 
% for now, we insist that u is a row vector 
% cepstral vector must include the 0'th coefficient 
% mode: 'c'  pow=exp(irdct(cep))   [default] 
%       'f'  pow=exp(rsfft(cep)/n)  [fft length even] 
%       'fo' pow=exp(rsfft(cep)/n)  [fft length odd] 
 
%      Copyright (C) Mike Brookes 1998 
% 
%      Last modified Wed Jan 30 09:44:15 2002 
% 
%   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. 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
 
if nargin<3 mode='c'; end 
if min(size(v))==1 
   v=diag(v); 
end 
if any(mode=='f') 
   n=2*length(u)-2; 
   if any(mode=='o') 
      n=n+1; 
   end 
   p=rsfft(u',n)/n; 
   q=rsfft(rsfft(v,n)',n)/n^2; 
else 
   p=irdct(u'); 
   q=irdct(irdct(v)'); 
end 
m=exp(p+0.5*diag(q))'; 
c=(m'*m).*(exp(q)-1);