--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/signal/inst/ss2tf.m	Fri Jan 06 14:28:55 2012 +0000
@@ -0,0 +1,66 @@
+## Copyright (C) 1996, 2000, 2004, 2005, 2007
+##               Auburn University.  All rights reserved.
+## Copyright (C) 2012 Lukas F. Reichlin
+##
+## 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 3 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 should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{num}, @var{den}] =} ss2tf (@var{a}, @var{b}, @var{c}, @var{d})
+## Conversion from transfer function to state-space.
+## The state space system:
+## @iftex
+## @tex
+## $$ \dot x = Ax + Bu $$
+## $$ y = Cx + Du $$
+## @end tex
+## @end iftex
+## @ifinfo
+## @example
+##       .
+##       x = Ax + Bu
+##       y = Cx + Du
+## @end example
+## @end ifinfo
+##
+## is converted to a transfer function:
+## @iftex
+## @tex
+## $$ G(s) = { { \rm num }(s) \over { \rm den }(s) } $$
+## @end tex
+## @end iftex
+## @ifinfo
+## @example
+##
+##                 num(s)
+##           G(s)=-------
+##                 den(s)
+## @end example
+## @end ifinfo
+##
+## @end deftypefn
+
+## Author: R. Bruce Tenison <btenison@eng.auburn.edu>
+## Created: June 24, 1994
+## a s hodel: modified to allow for pure gain blocks Aug 1996
+
+function [num, den] = ss2tf (varargin)
+
+  if (nargin == 0)
+    print_usage ();
+  endif
+
+  [num, den] = tfdata (ss (varargin{:}), "vector");
+
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/signal/inst/ss2zp.m	Fri Jan 06 14:28:55 2012 +0000
@@ -0,0 +1,39 @@
+## Copyright (C) 1996, 2000, 2004, 2005, 2006, 2007
+##               Auburn University. All rights reserved.
+## Copyright (C) 2012 Lukas F. Reichlin
+##
+## 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 3 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 should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{pol}, @var{zer}, @var{k}] =} ss2zp (@var{a}, @var{b}, @var{c}, @var{d})
+## Converts a state space representation to a set of poles and zeros;
+## @var{k} is a gain associated with the zeros.
+##
+## @end deftypefn
+
+## Author: David Clem
+## Created: August 15, 1994
+## Hodel: changed order of output arguments to zer, pol, k. July 1996
+## a s hodel: added argument checking, allow for pure gain blocks aug 1996
+
+function [z, p, k] = ss2zp (varargin)
+
+  if (nargin == 0)
+    print_usage ();
+  endif
+
+  [z, p, k] = zpkdata (ss (varargin{:}), "vector");
+
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/signal/inst/tf2ss.m	Fri Jan 06 14:28:55 2012 +0000
@@ -0,0 +1,67 @@
+## Copyright (C) 1996, 1998, 2000, 2002, 2004, 2005, 2007
+##               Auburn University.  All rights reserved.
+## Copyright (C) 2012 Lukas F. Reichlin
+##
+## 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 3 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 should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{a}, @var{b}, @var{c}, @var{d}] =} tf2ss (@var{num}, @var{den})
+## Conversion from transfer function to state-space.
+## The state space system:
+## @iftex
+## @tex
+## $$ \dot x = Ax + Bu $$
+## $$ y = Cx + Du $$
+## @end tex
+## @end iftex
+## @ifinfo
+## @example
+##       .
+##       x = Ax + Bu
+##       y = Cx + Du
+## @end example
+## @end ifinfo
+## is obtained from a transfer function:
+## @iftex
+## @tex
+## $$ G(s) = { { \rm num }(s) \over { \rm den }(s) } $$
+## @end tex
+## @end iftex
+## @ifinfo
+## @example
+##                 num(s)
+##           G(s)=-------
+##                 den(s)
+## @end example
+## @end ifinfo
+##
+## The state space system matrices obtained from this function 
+## will be in observable companion form as Wolovich's Observable
+## Structure Theorem is used.
+## @end deftypefn
+
+## Author: R. Bruce Tenison <btenison@eng.auburn.edu>
+## Created: June 22, 1994
+## mod A S Hodel July, Aug  1995
+
+function [a, b, c, d, e] = tf2ss (varargin)
+
+  if (nargin == 0)
+    print_usage ();
+  endif
+
+  [a, b, c, d, e] = dssdata (tf (varargin{:}), []);
+
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/signal/inst/tf2zp.m	Fri Jan 06 14:28:55 2012 +0000
@@ -0,0 +1,38 @@
+## Copyright (C) 1996, 1998, 2000, 2003, 2004, 2005, 2006, 2007
+##               Auburn University.  All rights reserved.
+## Copyright (C) 2012 Lukas F. Reichlin
+##
+## 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 3 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 should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{zer}, @var{pol}, @var{k}] =} tf2zp (@var{num}, @var{den})
+## Converts transfer functions to poles-and-zero representations.
+##
+## Returns the zeros and poles of the system defined 
+## by @var{num}/@var{den}.
+## @var{k} is a gain associated with the system zeros.
+## @end deftypefn
+
+## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu>
+
+function [z, p, k] = tf2zp (varargin)
+
+  if (nargin == 0)
+    print_usage ();
+  endif
+
+  [z, p, k] = zpkdata (tf (varargin{:}), "vector");
+
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/signal/inst/zp2ss.m	Fri Jan 06 14:28:55 2012 +0000
@@ -0,0 +1,69 @@
+## Copyright (C) 1996, 2000, 2002, 2003, 2004, 2005, 2007
+##               Auburn University.  All rights reserved.
+## Copyright (C) 2012 Lukas F. Reichlin
+##
+## 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 3 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 should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{a}, @var{b}, @var{c}, @var{d}] =} zp2ss (@var{zer}, @var{pol}, @var{k})
+## Conversion from zero / pole to state space.
+##
+## @strong{Inputs}
+## @table @var
+## @item zer
+## @itemx pol
+## Vectors of (possibly) complex poles and zeros of a transfer
+## function. Complex values must come in conjugate pairs
+## (i.e., @math{x+jy} in @var{zer} means that @math{x-jy} is also in @var{zer}).
+## @item k
+## Real scalar (leading coefficient).
+## @end table
+##
+## @strong{Outputs}
+## @table @var
+## @item @var{a}
+## @itemx @var{b}
+## @itemx @var{c}
+## @itemx @var{d}
+## The state space system, in the form:
+## @iftex
+## @tex
+## $$ \dot x = Ax + Bu $$
+## $$ y = Cx + Du $$
+## @end tex
+## @end iftex
+## @ifinfo
+## @example
+##      .
+##      x = Ax + Bu
+##      y = Cx + Du
+## @end example
+## @end ifinfo
+## @end table
+## @end deftypefn
+
+## Author: David Clem
+## Created: August 15, 1994
+
+function [a, b, c, d, e] = zp2ss (varargin)
+
+  if (nargin == 0)
+    print_usage ();
+  endif
+
+  [a, b, c, d, e] = dssdata (zpk (varargin{:}), []);
+
+endfunction
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main/signal/inst/zp2tf.m	Fri Jan 06 14:28:55 2012 +0000
@@ -0,0 +1,45 @@
+## Copyright (C) 1996, 1998, 2000, 2002, 2004, 2005, 2007
+##               Auburn University.  All rights reserved.
+## Copyright (C) 2012 Lukas F. Reichlin
+##
+## 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 3 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 should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- 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 @var
+## @item zer
+## @itemx pol
+## Vectors of (possibly complex) poles and zeros of a transfer
+## function.  Complex values must appear in conjugate pairs.
+## @item k
+## Real scalar (leading coefficient).
+## @end table
+## @end deftypefn
+
+## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu>
+## (With help from students Ingram, McGowan.)
+
+function [num, den] = zp2tf (varargin)
+
+  if (nargin == 0)
+    print_usage ();
+  endif  
+
+  [num, den] = tfdata (zpk (varargin{:}), "vector");
+
+endfunction