Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/signal-1.1.3/nuttallwin.m b/octave_packages/signal-1.1.3/nuttallwin.m
new file mode 100644 (file)
index 0000000..5493768
--- /dev/null
+++ b/octave_packages/signal-1.1.3/nuttallwin.m
@@ -0,0 +1,42 @@
+## Copyright (C) 2007 Sylvain Pelissier <sylvain.pelissier@gmail.com>
+##
+## 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{w}] =} nuttallwin(@var{L})
+## Compute the Blackman-Harris window defined by Nuttall of length L.
+## @seealso{blackman, blackmanharris}
+## @end deftypefn
+
+function [w] = nuttallwin(L)
+  if (nargin != 1); print_usage; end
+
+  if(L < 0)
+    error('L must be positive');
+  end
+
+  if(L ~= floor(L))
+    L = round(L);
+    warning('L rounded to the nearest integer.');
+  end
+
+  N = L-1;
+  a0 = 0.355768;
+  a1 = 0.487396;
+  a2 = 0.144232;
+  a3 = 0.012604;
+  n = -N/2:N/2;
+  w = a0 + a1.*cos(2.*pi.*n./N) + a2.*cos(4.*pi.*n./N) + a3.*cos(6.*pi.*n./N);
+  w = w';
+endfunction