Mercurial > octave
view scripts/control/ss2tf.m @ 3346:8dd4718801fd
[project @ 1999-11-09 18:18:12 by jwe]
author | jwe |
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date | Tue, 09 Nov 1999 18:18:37 +0000 |
parents | f7e4a95916f2 |
children | 69b167451491 |
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# Copyright (C) 1996 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 } { outputs =} ss2tf ( inputs ) ## @format ## [num,den] = ss2tf(a,b,c,d) ## Conversion from tranfer function to state-space. ## The state space system ## . ## x = Ax + Bu ## y = Cx + Du ## ## is converted to a transfer function ## ## num(s) ## G(s)=------- ## den(s) ## ## used internally in system data structure format manipulations ## ## ## @end format ## @end deftypefn function [num,den] = ss2tf(a,b,c,d) # Written by R. Bruce Tenison (June 24, 1994) btenison@eng.auburn.edu # a s hodel: modified to allow for pure gain blocks Aug 1996 # Check args [n,m,p] = abcddim(a,b,c,d); if (n == -1) num = []; den = []; error("ss2tf: Non compatible matrix arguments"); elseif ( (m != 1) | (p != 1)) num = []; den = []; error(["ss2tf: not SISO system: m=",num2str(m)," p=",num2str(p)]); endif if(n == 0) # gain block only num = d; den = 1; else # First, get the denominator coefficients den = poly(a); # Get the zeros of the system [zz,g] = tzero(a,b,c,d); # Form the Numerator (and include the gain) if (!isempty(zz)) num = g * poly(zz); else num = g; endif # the coefficients must be real den = real(den); num = real(num); endif endfunction