www.pudn.com > voicebox2.zip > LPCPF2CC.M

function cc=lpcpf2cc(pf,np) 
%LPCPF2CC Convert power spectrum to complex cepstrum CC=(PF,NP) 
% Note this conversion is not exact unless the pf() spectrum is much > np 
 
%      Copyright (C) Mike Brookes 1998 
% 
%      Last modified Tue May 12 16:20:30 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. 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
 
if nargin<2 np=size(pf,2)-2; end 
cc=irfft(log(pf.')).'; 
cc(:,1)=[]; 
[nf,p]=size(cc); 
if np>p 
   cc=[cc zeros(nf,np-p)]; 
else 
   cc(:,np+1:p)=[]; 
end