V_LPCZZ2SS Convert z-plane poles to s-plane poles SS=(ZZ) the s-plane is in units of Normalized Hz and so the imaginary part of each ss() value is in the range +-0.5 If you multiply ss by the sample frequency, a formant with frequency f and bandwidth b will give an s-plane pole-pair of approximately -b/2 +-j*f The inverse function is zz=v_lpcss2zz(ss)
0001 function ss=v_lpczz2ss(zz) 0002 %V_LPCZZ2SS Convert z-plane poles to s-plane poles SS=(ZZ) 0003 %the s-plane is in units of Normalized Hz and so the imaginary part 0004 % of each ss() value is in the range +-0.5 0005 % 0006 % If you multiply ss by the sample frequency, a formant with 0007 % frequency f and bandwidth b will give an s-plane pole-pair 0008 % of approximately -b/2 +-j*f 0009 % 0010 % The inverse function is zz=v_lpcss2zz(ss) 0011 0012 0013 % Copyright (C) Mike Brookes 1997 0014 % Version: $Id: v_lpczz2ss.m 10865 2018-09-21 17:22:45Z dmb $ 0015 % 0016 % VOICEBOX is a MATLAB toolbox for speech processing. 0017 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0018 % 0019 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0020 % This program is free software; you can redistribute it and/or modify 0021 % it under the terms of the GNU Lesser General Public License as published by 0022 % the Free Software Foundation; either version 3 of the License, or 0023 % (at your option) any later version. 0024 % 0025 % This program is distributed in the hope that it will be useful, 0026 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0027 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0028 % GNU Lesser General Public License for more details. 0029 % 0030 % You can obtain a copy of the GNU Lesser General Public License from 0031 % https://www.gnu.org/licenses/ . 0032 % See files gpl-3.0.txt and lgpl-3.0.txt included in this distribution. 0033 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0034 0035 ss=log(max(zz,1e-8))*0.5/pi;