window

 window - Return a window of a given shape for smoothing data.

 USAGE:
  w = window(N,wt)

 DESCRIPTION:
  generate a window function

 INPUT:
  N = length of desired window
  wt = window type desired
       'rect' = rectangular        'tria' = triangular (Bartlett)
       'hann' = Hanning            'hamm'  = Hamming
       'blac' = Blackman

 OUTPUT
  w = row vector containing samples of the desired window

 SEE ALSO:
  weim.m

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0001 function w = window(N,wt)
0002 % window - Return a window of a given shape for smoothing data.
0003 %
0004 % USAGE:
0005 %  w = window(N,wt)
0006 %
0007 % DESCRIPTION:
0008 %  generate a window function
0009 %
0010 % INPUT:
0011 %  N = length of desired window
0012 %  wt = window type desired
0013 %       'rect' = rectangular        'tria' = triangular (Bartlett)
0014 %       'hann' = Hanning            'hamm'  = Hamming
0015 %       'blac' = Blackman
0016 %
0017 % OUTPUT
0018 %  w = row vector containing samples of the desired window
0019 %
0020 % SEE ALSO:
0021 %  weim.m
0022 %
0023 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0024 nn = N-1;
0025 pn = 2*pi*(0:nn)/nn;
0026 if wt(1,1:4) == 'rect',
0027                         w = ones(1,N);
0028 elseif wt(1,1:4) == 'tria',
0029                         m = nn/2;
0030                         w = (0:m)/m;
0031                         w = [w w(ceil(m):-1:1)];
0032 elseif wt(1,1:4) == 'hann',
0033                         w = 0.5*(1 - cos(pn));
0034 elseif wt(1,1:4) == 'hamm',
0035                         w = .54 - .46*cos(pn);
0036 elseif wt(1,1:4) == 'blac',
0037                         w = .42 -.5*cos(pn) + .08*cos(2*pn);
0038 else
0039                         disp('Incorrect Window type requested')
0040 end