Mercurial > octave
view scripts/control/zp2tf.m @ 3385:10f21f7ccc7f
[project @ 1999-12-15 22:28:26 by jwe]
author | jwe |
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date | Wed, 15 Dec 1999 22:28:52 +0000 |
parents | 69b167451491 |
children | eb4223985ca8 |
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## Copyright (C) 1996,1998 Auburn University. All Rights Reserved ## ## This file is part of Octave. ## ## Octave 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, or (at your option) any ## later version. ## ## Octave 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 should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, write to the Free ## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. ## -*- texinfo -*- ## @deftypefn {Function File } {[@var{num}, @var{den}] =} zp2tf (@var{zer}, @var{pol}, @var{k}) ## Converts zeros / poles to a transfer function. ## @strong{Inputs} ## @table ## @item zer, pol ## vectors of (possibly complex) poles and zeros of a transfer ## function. Complex values should appear in conjugate pairs ## @item k ## real scalar (leading coefficient) ## @end table ## @code{[num,den] = zp2tf(zer,pol,k)} forms the transfer function ## @code{num/den} from the vectors of poles and zeros. ## @end deftypefn function [num, den] = zp2tf (zer, pol, k) ## Find out whether data was entered as a row or a column vector and ## convert to a column vector if necessary ## Written by A. S. Hodel with help from students Ingram, McGowan. ## a.s.hodel@eng.auburn.edu [rp,cp] = size(pol); [rz,cz] = size(zer); if(!(is_vector(zer) | isempty(zer)) ) error(sprintf("zer(%dx%d) must be a vector",rz,cz)); elseif(!(is_vector(pol) | isempty(pol)) ) error(sprintf("pol(%dx%d) must be a vector",rp,cp)); elseif(length(zer) > length(pol)) error(sprintf("zer(%dx%d) longer than pol(%dx%d)",rz,cz,rp,cp)); endif ## initialize converted polynomials num = k; den = 1; ## call zp2ssg2 if there are complex conjugate pairs left, otherwise ## construct real zeros one by one. Repeat for poles. while(!isempty(zer)) if( max(abs(imag(zer))) ) [poly,zer] = zp2ssg2(zer); else poly = [1 -zer(1)]; zer = zer(2:length(zer)); endif num = conv(num,poly); endwhile while(!isempty(pol)) if( max(abs(imag(pol))) ) [poly,pol] = zp2ssg2(pol); else poly = [1 -pol(1)]; pol = pol(2:length(pol)); endif den = conv(den,poly); endwhile endfunction