R/hanning.R

In signal: Signal Processing

## Copyright (C) 1995, 1996, 1997  Andreas Weingessel
##
## This file is part of Octave.
##
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## the Free Software Foundation; either version 2, or (at your option)
## any later version.
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## General Public License for more details.
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## -*- texinfo -*-
## @deftypefn {Function File} {} hanning (@var{m})
## Return the filter coefficients of a Hanning window of length @var{m}.
##
## For a definition of this window type, see e.g. A. V. Oppenheim &
## R. W. Schafer, "Discrete-Time Signal Processing".
## @} # deftypefn

## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
## Description: Coefficients of the Hanning window

hanning  <- function(n)  {

  if (! (length(n) == 1 && (n == round(n)) && (n > 0)))
    stop("hanning: n has to be an integer > 0")

  if (n == 1)
    c = 1
  else {
    n = n - 1
    c = 0.5 - 0.5 * cos(2 * pi * (0:n) / n)
  }
  c
}