# Hann window function: hann_window

### 15.2.21 Hann window function: hann_window

The hann_window command finds a Hann window of a sequence.

- hann_window takes one mandatory argument and one optional argument:
  - v, a real vector with length n.
  - Optionally, an interval n0..n1 (by default 0..(n−1)).
- hann_window(v ⟨,n1..n2⟩) returns the elementwise product of [vn1,…,vn2] and the vector w of length N=n2−n1+1 defined by

  wk=sin2

  ⎛
  ⎜
  ⎜
  ⎝

  k π
  N−1

  ⎞
  ⎟
  ⎟
  ⎠

  for k=0,1,…,N−1.

#### Example.

Input:

L0:=randvector(1000,0..1):;
scatterplot(L0);

Output:

Input:

L:=hann_window(L0,2):;
scatterplot(L);

Output: