## Copyright (C) 2007 Muthiah Annamalai <muthiah.annamalai@uta.edu>
##
## 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}] =} blackmannuttall (@var{L})
## Compute the Blackman-Nuttall window.
## @seealso{nuttallwin, kaiser}
## @end deftypefn

function [w] = blackmannuttall(L)

  if (nargin < 1)
    print_usage;
  elseif (! isscalar(L))
    error("L must be a number");
  endif

  if (L == 1)
    w = 1;
  else
    N = L-1;
    a0 = 0.3635819;
    a1 = 0.4891775;
    a2 = 0.1365995;
    a3 = 0.0106411;
    n = 0:N;
    w = a0 - a1.*cos(2.*pi.*n./N) + a2.*cos(4.*pi.*n./N) - a3.*cos(6.*pi.*n./N);
    w = w.';
  endif

endfunction
