Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / control-2.3.52 / gensig.m

diff --git a/octave_packages/control-2.3.52/gensig.m b/octave_packages/control-2.3.52/gensig.m
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+## Copyright (C) 2009, 2010, 2011   Lukas F. Reichlin
+##
+## This file is part of LTI Syncope.
+##
+## LTI Syncope 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.
+##
+## LTI Syncope 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 LTI Syncope.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn{Function File} {[@var{u}, @var{t}] =} gensig (@var{sigtype}, @var{tau})
+## @deftypefnx{Function File} {[@var{u}, @var{t}] =} gensig (@var{sigtype}, @var{tau}, @var{tfinal})
+## @deftypefnx{Function File} {[@var{u}, @var{t}] =} gensig (@var{sigtype}, @var{tau}, @var{tfinal}, @var{tsam})
+## Generate periodic signal.  Useful in combination with lsim.
+##
+## @strong{Inputs}
+## @table @var
+## @item sigtype = "sin"
+## Sine wave.
+## @item sigtype = "cos"
+## Cosine wave.
+## @item sigtype = "square"
+## Square wave.
+## @item sigtype = "pulse"
+## Periodic pulse.
+## @item tau
+## Duration of one period in seconds.
+## @item tfinal
+## Optional duration of the signal in seconds.  Default duration is 5 periods.
+## @item tsam
+## Optional sampling time in seconds.  Default spacing is tau/64.
+## @end table
+##
+## @strong{Outputs}
+## @table @var
+## @item u
+## Vector of signal values.
+## @item t
+## Time vector of the signal.
+## @end table
+##
+## @seealso{lsim}
+## @end deftypefn
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: August 2009
+## Version: 0.4
+
+function [u, t] = gensig (sigtype, tau, tfinal, tsam)
+
+  if (nargin < 2 || nargin > 4)
+    print_usage ();
+  endif
+
+  if (! ischar (sigtype))
+    error ("gensig: first argument must be a string");
+  endif
+
+  if (! issample (tau))
+    error ("gensig: second argument is not a valid period");
+  endif
+
+  if (nargin < 3)
+    tfinal = 5 * tau;
+  elseif (! issample (tfinal))
+    error ("gensig: third argument is not a valid final time");
+  endif
+
+  if (nargin < 4)
+    tsam = tau / 64;
+  elseif (! issample (tsam))
+    error ("gensig: fourth argument is not a valid sampling time");
+  endif
+
+  t = reshape (0 : tsam : tfinal, [], 1);
+
+  switch (lower (sigtype(1:2)))
+    case "si"
+      u = sin (2*pi/tau * t);
+    case "co"
+      u = cos (2*pi/tau * t);
+    case "sq"
+      u = double (rem (t, tau) >= tau/2);
+    case "pu"
+      u = double (rem (t, tau) < (1 - 1000*eps) * tsam);
+    otherwise
+      error ("gensig: '%s' is an invalid signal type", sigtype);
+  endswitch
+
+endfunction
+