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a
I 2
CCII
I 1
z−
y
I 3
1
CCII
x
z+
C 1
z−
y
I 03
I 02
2
R 2
R 1
x
z+
C 2
CCII
z−
x
3
I 01
y
z+
b
CCII
I in
z−
y
I 02
1
CCII
x
z+
z−
C 1
y
I 03
R 2
2
z+
R 1
x
C 2
CCII
x
z−
3
I 01
z−
z+
y
Fig. 12.51 CM Biquads using CCs proposed by Wang and Lee [ 133 ](a) MIMO-type (b) SIMO-
type
Now if I 01 as the output current, then the various filter responses realized are given
by:(i) HPF: I 1 ¼
I 2 ¼
0 and I 3 ¼
Iin; BPF: I 1 ¼
I 3 ¼
0 and I 2 ¼
Iin and LPF:
I 3 ¼
Iin. Figure 12.51a can also function as a single input three
output universal biquad filter if I 1 ¼
I 2 ¼
0 and I 1 ¼
I 3 ¼
0 and I 2 ¼
I in . The three current transfer
functions can be given by:
C 2 R 2
Ds
1
1
C 1 R 1 C 2 R 2
s
s 2
Ds
I 01
I in ¼
I 02
I in ¼
and I 03
I in ¼
ð
12
:
183
Þ
;
ðÞ
Ds
ðÞ
ðÞ
Therefore, the configuration yields BPF at I 01 , LPF at I 02 and HPF at I 03 simulta-
neously. The Notch and APF can easily be obtained by combining appropriate
currents.
Figure 12.51b shows the single input three output filter configuration. The
structure uses multiple output CCII in place of CCIII. Using standard ideal port
relations of the CCs, the three filter transfer functions can be obtained as:
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