1 ## Copyright (C) 1994-1996, 1998, 2000, 2002, 2004, 2005, 2007 Auburn University
2 ## Copyright (C) 2012 Lukas F. Reichlin <lukas.reichlin@gmail.com>
4 ## This program is free software; you can redistribute it and/or modify it under
5 ## the terms of the GNU General Public License as published by the Free Software
6 ## Foundation; either version 3 of the License, or (at your option) any later
9 ## This program is distributed in the hope that it will be useful, but WITHOUT
10 ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
14 ## You should have received a copy of the GNU General Public License along with
15 ## this program; if not, see <http://www.gnu.org/licenses/>.
18 ## @deftypefn {Function File} {[@var{a}, @var{b}, @var{c}, @var{d}] =} tf2ss (@var{num}, @var{den})
19 ## Conversion from transfer function to state-space.
20 ## The state space system:
23 ## $$ \dot x = Ax + Bu $$
34 ## is obtained from a transfer function:
37 ## $$ G(s) = { { \rm num }(s) \over { \rm den }(s) } $$
48 ## The state space system matrices obtained from this function
49 ## will be in observable companion form as Wolovich's Observable
50 ## Structure Theorem is used.
53 ## Author: R. Bruce Tenison <btenison@eng.auburn.edu>
55 function [a, b, c, d, e] = tf2ss (varargin)
61 [a, b, c, d, e] = dssdata (tf (varargin{:}), []);