X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fm%2Fsignal%2Fhamming.m;fp=octave_packages%2Fm%2Fsignal%2Fhamming.m;h=154b24fd0b8f899dc5f44ad116fee941b92006ce;hp=0000000000000000000000000000000000000000;hb=1c0469ada9531828709108a4882a751d2816994a;hpb=63de9f36673d49121015e3695f2c336ea92bc278 diff --git a/octave_packages/m/signal/hamming.m b/octave_packages/m/signal/hamming.m new file mode 100644 index 0000000..154b24f --- /dev/null +++ b/octave_packages/m/signal/hamming.m @@ -0,0 +1,61 @@ +## Copyright (C) 1995-2012 Andreas Weingessel +## +## This file is part of Octave. +## +## Octave 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. +## +## Octave 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 Octave; see the file COPYING. If not, see +## . + +## -*- texinfo -*- +## @deftypefn {Function File} {} hamming (@var{m}) +## Return the filter coefficients of a Hamming window of length @var{m}. +## +## For a definition of the Hamming window, see e.g., A. V. Oppenheim & +## R. W. Schafer, @cite{Discrete-Time Signal Processing}. +## @end deftypefn + +## Author: AW +## Description: Coefficients of the Hamming window + +function c = hamming (m) + + if (nargin != 1) + print_usage (); + endif + + if (! (isscalar (m) && (m == fix (m)) && (m > 0))) + error ("hamming: M has to be an integer > 0"); + endif + + if (m == 1) + c = 1; + else + m = m - 1; + c = 0.54 - 0.46 * cos (2 * pi * (0:m)' / m); + endif + +endfunction + +%!assert (hamming (1), 1); +%!assert (hamming (2), (0.54 - 0.46)*ones(2,1)); +%!assert (hamming (16), fliplr (hamming (16))); +%!assert (hamming (15), fliplr (hamming (15))); +%!test +%! N = 15; +%! A = hamming (N); +%! assert (A (ceil (N/2)), 1); + +%!error hamming (); +%!error hamming (0.5); +%!error hamming (-1); +%!error hamming (ones(1,4));