6/13/2005
Filter Approximation Theory
6
Butterworth
•
F(
w
) =
w
n
and
e
= 1 and
•
•
•
•
•
Characteristics
–
Smooth transfer function (no ripple)
–
Maximally flat and Linear phase (in the pass-band)
–
Slow cutoff
L
|H(
w
)|
2
1
w