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I 2
CCII-
CCII-
R 4
I 1
CCII+
CCII+
V 2
x
V 1
x
y
y
y
z
z
z
R 2
z
y
x
R 5
x
C 1
C 2
R 3
R 1
Fig. 5.48 Mutually-coupled circuit proposed by Yuce et al. [ 124 ]
from where it is seen that equivalent parameters i.e. the two self- inductances and
mutual inductance are given by:
L 1 ¼
C 1 R 1 R 3 , L 2 ¼
C 1 R 2 R 3 , M
¼
C 1 R m R 3
ð
5
:
55
Þ
Another circuit for simulating a mutual-coupled circuit employing only four CCs
two of which are CCII
with complete circuit requiring as many as six CCIIs was
proposed by Yuce et al. [ 124 ] and is shown in Fig. 5.48 . This mutually-coupled
circuit is characterized by the following matrix equation.
¼
I 1
I 2
V 1
V 2
sL 1 þ
ð
M 11
Þ
sM 12
ð
5
:
56
Þ
sM 21
sL 2 þ
ð
M 22
Þ
where
L 1 ¼
C 1 R 1 R 2 , L 2 ¼
C 2 R 3 R 4
ð
5
:
57
Þ
M 11 ¼
M 12 ¼
M 1 ¼
C 1 R 1 R 5 ;
M 21 ¼
M 22 ¼
M 2 ¼
C 2 R 3 R 5
ð
5
:
58
Þ
If one takes C 1 R 1 ¼
M is obtained.
It may be mentioned that both the circuits suffer from the drawback of requiring
a large number of CCIIs (six in the circuit of Fig. 5.47 and four in the circuit of
Fig. 5.48 ) as well as using two capacitors at the X-terminal of the current conveyor
which is often associated with stability problems [ 116 ]. Thus, there is enough scope
for devising improved alternative realizations of the mutually-coupled circuits, free
from these difficulties.
C 2 R 3 ,M 1 ¼
M 2 ¼
5.3.12 Grounded and Floating MOS VCRs
and Transconductors
In many applications, electronically-variable resistors and other impedances are
required for achieving electronic control of the parameters of the functional circuits
incorporating such impedances. Several authors have presented circuits to realize
 
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