www.pudn.com > voicebox2.zip > LPCCW2ZZ.M

function zz=lpccw2zz(cw) 
%LPCPZ2ZZ LPC: Power spectrum roots to LPC poles ZZ=(CW) 
% pz are the roots of the power spectrum polynomial pp(cos(w)) 
 
%      Copyright (C) Mike Brookes 1998 
% 
%      Last modified Tue Feb  5 18:06:44 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 
% 
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%   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. 
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%   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. 
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zs=sqrt(cw.^2-1); 
zz=cw-sign(real(conj(cw).*zs)).*zs;