Hardware Reference
In-Depth Information
employing CCCIIs for both VM and CM filter designs. In the following, we present
a CCCII-based implementation of the CM KHN-equivalent biquad (see Fig.
9.27
).
A routine analysis of this circuit reveals that the three transfer functions of
interest for this circuit are given by:
1
C
1
C
2
R
x
1
R
x
2
Ds
s
C
1
R
x
1
Ds
I
i
2
¼
s
2
Ds
I
out
I
i
1
¼
I
out
and
I
out
I
i
3
¼
ð
9
:
29
Þ
ðÞ
;
ðÞ
ðÞ
Where
R
x
3
C
1
R
x
1
R
x
5
þ
R
x
3
R
x
4
C
1
C
2
R
x
1
R
x
2
s
2
Ds
ðÞ
¼
þ
s
ð
9
:
30
Þ
so that the parameters
ˉ
0
and
Q
0
are given by:
r
R
x
3
R
x
4
C
1
C
2
R
x
1
R
x
2
r
C
1
R
x
1
C
2
R
x
2
R
x
3
R
x
4
ˉ
0
¼
and
Q
0
¼
R
x
5
ð
9
:
31
Þ
Thus, the circuit can realize three basic functions as above. In addition, a notch
response is realizable for the case when I
i1
¼
I
i3
¼
I
i
along with I
i2
¼
0 as well as
R
x3
¼
R
x4
. Lastly, an all pass response is realizable for I
i1
¼
I
i2
¼
I
i3
¼
I
i
along with
R
x3
¼
R
x4
.
I
B5
I
i3
I
i2
Y
5
Z
X
CCCII−
I
B3
I
B1
I
B2
I
i1
Y
Z
X
Y
1
3
I
out
2
Z
CCCII+
Z
C
2
CCCII+
C
1
Y
X
X
CCCII+
I
B4
Y
4
Z
X
CCCII−
Fig. 9.27 A CM KHN-equivalent biquad using CCCIIs presented by Altuntas and Toker
(Adapted from [
24
]
2002, Urban and Fischer Verlag)
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