Hardware Reference
In-Depth Information
The filter parameters
ω
0
and Q
0
can be determined as:
s
C
1
R
2
r
1
C
1
C
2
R
2
R
1
R
3
R
2
þ
C
2
R
1
ω
0
¼
and
Q
0
¼
ð
12
:
157
Þ
R
3
From the equation (
12.157
), it is clear that
ω
0
can be controlled by R
1
and /or R
2
and
Q
0
can be varied by R
3
. Hence, both
ω
0
and Q
0
are orthogonally controllable.
12.2.12 Filter Design Using Dual/Multi Output CCs (DOCC/
MOCC)
In this section of this chapter we include some universal filter configurations using
dual output CCs (DOCC) and multiple-output CCs (MOCCs) from amongst a large
number of circuits available in literature [
124
-
194
]. In fact, DOCCs/MOCCs have
been two of the most prominent varieties of CCs which have been more popularly
employed than others in the analog circuits
literature.
In the following therefore, we highlight a variety of universal biquads employing
DOCCs/MOCCs.
Senani-Singh-Singh-Bhaskar universal CM biquad Figure
12.45
shows a set of
tunable universal CM biquads realizable with only three multi-output-current-
conveyors (MOCCs) and all grounded passive elements proposed by Senani
et al. [
130
].
The realized structures provide tunability of all the three filter parameters
namely, bandwidth, angular frequency and gain (H
0
). When MOCCs are
implemented as current-controlled-conveyors with multiple outputs, one of the
new circuits becomes a novel electronically controllable universal CM biquad.
Assuming MOCCs to be characterized by i
y
¼
'
i
x
,
it can be shown that the current transfer functions of all the configurations remain
same and can be given by:
i
x
and i
z
¼
0, v
x
¼
v
y
,i
z
+
¼
r
1
Ds
r
1
sC
2
R
2
r
1
s
2
C
1
C
2
R
1
R
2
Ds
r
2
r
2
r
2
ð
Þ
I
01
I
in
¼
I
02
I
in
¼
and
I
03
I
in
¼
ð
12
:
158
Þ
ðÞ
;
Ds
ðÞ
ðÞ
where
s
2
C
1
C
2
R
1
R
2
þ
Ds
ðÞ¼
sC
2
R
2
þ
ð
:
Þ
1
12
159
The different filter parameters of the realized functions can be given by:
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