--- /dev/null
+## Copyright (C) 1995-2012 Friedrich Leisch
+##
+## 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
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} rectangle_lw (@var{n}, @var{b})
+## Rectangular lag window. Subfunction used for spectral density
+## estimation.
+## @end deftypefn
+
+## Author: FL <Friedrich.Leisch@ci.tuwien.ac.at>
+## Description: Rectangular lag window
+
+function retval = rectangle_lw (n, b)
+
+ if (nargin != 2)
+ print_usage ();
+ endif
+
+ retval = zeros (n, 1);
+ t = floor (1 / b);
+
+ retval (1:t, 1) = ones (t, 1);
+
+endfunction