Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / signal-1.1.3 / sawtooth.m

diff --git a/octave_packages/signal-1.1.3/sawtooth.m b/octave_packages/signal-1.1.3/sawtooth.m
new file mode 100644 (file)
index 0000000..7707d8f
--- /dev/null
+++ b/octave_packages/signal-1.1.3/sawtooth.m
@@ -0,0 +1,59 @@
+## Copyright (C) 2007 Juan Aguado
+##
+## 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; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{y}] =} sawtooth(@var{t})
+## @deftypefnx {Function File} {[@var{y}] =} sawtooth(@var{t},@var{width})
+## Generates a sawtooth wave of period @code{2 * pi} with limits @code{+1/-1}
+##  for the elements of @var{t}.
+##
+## @var{width} is a real number between @code{0} and @code{1} which specifies
+## the point between @code{0} and @code{2 * pi} where the maximum is. The
+## function increases linearly from @code{-1} to @code{1} in  @code{[0, 2 * 
+## pi * @var{width}]} interval, and decreases linearly from @code{1} to 
+## @code{-1} in the interval @code{[2 * pi * @var{width}, 2 * pi]}.
+##
+## If @var{width} is 0.5, the function generates a standard triangular wave.
+##
+## If @var{width} is not specified, it takes a value of 1, which is a standard
+## sawtooth function.
+## @end deftypefn
+
+function y = sawtooth (t,width)
+
+  if (nargin < 1 || nargin > 2)
+    print_usage ();
+  endif
+
+  if (nargin == 1)
+    width = 1;
+  else
+    if (width < 0 || width > 1 || ! isreal (width))
+      error ("width must be a real number between 0 and 1.");
+    endif
+  endif
+
+  t = mod (t / (2 * pi), 1);
+  y = zeros (size (t));
+
+  if (width != 0)
+    y (t < width) = 2 * t (t < width) / width - 1;
+  endif
+
+  if (width != 1)
+    y( t >= width) = -2 * (t (t >= width) - width) / (1 - width) + 1;
+  endif
+
+endfunction