(4)
For the sake of completeness, here is a summary of the details:
Filter Type
L
f
(
ω
)
Type I
(
M
-
1)
∕
2
1
Type II
(
M
-
2)
∕
2
cos
(
ω∕
2)
Type III
(
M
-
3)
∕
2
sin
(
ω
)
Type IV
(
M
-
2)
∕
2
sin
(
ω∕
2)