Hardware Reference
In-Depth Information
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
Search WWH ::
Custom Search