IIR Filter
yn=-∑k=1M-1
a
k
yn-k+∑k=0M-1
b
k
xn-k
y
n
k
1
M
1
a
k
y
n
k
k
0
M
1
b
k
x
n
k
Hz=
b
0
+
b
1
z-1+
b
2
z-2+...+
b
M
z-M1+
a
1
z-1+
a
2
z-2+...+
a
M
z-M
H
z
b
0
b
1
z
-1
b
2
z
-2
...
b
M
z
M
1
a
1
z
-1
a
2
z
-2
...
a
M
z
M
IIR Filter Design Problem
Choose
a
i
a
i
,
b
i
b
i
to best approximate some
desired
|
H
d
w|
H
d
w
or, (occasionally),
H
d
w
H
d
w
.
As before, different design techniques will be
developed for different approximation criteria.
Outline of IIR Filter Design Material
- Bilinear Transform -
Maps
∥L∥∞
L
optimal (and other) analog
filter designs to
∥L∥∞
L
optimal digital IIR filter designs.
- Prony's Method -
Quasi-
∥L∥2
2
L
optimal method for time-domain fitting of a
desired impulse response (ad
hoc).
- Lp Optimal Design -
∥L∥p
p
L
optimal filter design (1<p<∞
1
p
) using non-linear optimization techniques.