15.2.17 Cosine window function:
cosine_window
The
cosine_window
command finds a cosine window of a sequence.
cosine_window
takes one mandatory argument and two optional arguments:
v
, a real vector with length
n
.
Optionally, α, a real number (by default 1).
Optionally, an interval
n
0
..
n
1
(by default 0..(
n
−1)).
cosine_window(
v
⟨,α,
n
1
..
n
2
⟩
)
returns the elementwise product of [
v
n
1
,…,
v
n
2
] and the vector
w
of length
N
=
n
2
−
n
1
+1 defined by
w
k
=sin
α
⎛
⎜
⎜
⎝
k
π
N
−1
⎞
⎟
⎟
⎠
for
k
=0,1,…,
N
−1.
Example.
Input:
L0:=randvector(1000,0..1):;
scatterplot(L0);
Output:
Input:
L:=cosine_window(L0,1.5):;
scatterplot(L);
Output: