www.pudn.com > voicebox2.zip > LPCFQ2ZZ.M

function zz=lpcfq2zz(f,q) 
%LPCFQ2ZZ Convert frequencies and q factors to z-plane poles ZZ=(F,Q) 
%all input values are in normalized Hz 
% roots are at exp(2*pi*f*(-1/(2q) +- j) 
% if f has more columns than q, remaining columns are real roots at -f 
 
%      Copyright (C) Mike Brookes 1998 
% 
%      Last modified Tue May 12 16:07:44 1998 
% 
%   VOICEBOX home page: 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. 
% 
%   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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[nf,pf]=size(f); 
if nargin < 2 
   pq=0; 
else 
   pq=size(q,2); 
end; 
zz=zeros(nf,pf+pq); 
if pq 
   ii=1:pq; 
   zz(:,2*ii-1)=exp(pi*f(:,ii).*(2i-q.^(-1))); 
   zz(:,2*ii)=conj(zz(:,2*ii-1)); 
end 
if pf>pq 
   ii=1+pq:pf; 
   zz(:,ii+pq)= exp(-2*pi*f(:,ii)); 
end