hanning window

Hello,

what is the difference between hanning and hann? They are both supposed to be returning hanning window sequences.

-obli

Answer 1

[Wayne King]

The Hann and Hanning window are both implemented in MATLAB by the same basic equation

w = 0.5 - 0.5*cos(2*pi*x);

There is a slight difference in the way they are calculated in hann.m and hanning.m based on the "x" vector that is evaluated in that equation.

For hann.m

hann(5) gives you

      x = (0:2)'./4;
      w = 0.5 - 0.5*cos(2*pi*x);
      w = [w ; w(end-1:-1:1)]

whereas hanning(5) gives you

    x = (1:3)'./6;
    w = 0.5-0.5*cos(2*pi*x);
    w = [w ; w(end-1:-1:1)];

Since the time vector in hann.m starts with 0, you get 0 as the first and last sample with hann.m, but not with hanning.m which starts with 1 as the first element of the time vector.

But they are the same equation and I think you can use which every implementation you want.

Answer 2

[Wayne King]

There is no difference. The hanning window, or hann window, or von Hann window were named after Julius von Hann. The hamming window is in honor of Richard Hamming. People just refer to the hann window as hanning just for symmetry with hamming. They are both generalized cosine windows.

[oblivious]

>> hann(5)

ans =

0

0.5000

1.0000

0.5000

0

>> hanning(5)

ans =

0.2500

0.7500

1.0000

0.7500

0.2500

then why does matlab returns different values?