Hardware Reference
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V CC
V CC
i s3
R s1
P 3
X 3
V A
Y 3
CCCII
I s1
i s1
R c2
Z 3
Q 3
P 1
X 1
V CC
I out
R L
Y 1
CCCII
R c1
+
Z 1
Q 1
V EE
V in
X 4
P 4
I s3
CCCII
Y 4
V B
Z 4
Q 4
R s3
V EE
V EE
Fig. 9.45 Frequency doubler proposed in [ 44 ]
Frequency doubler is widely used in analog signal processing, communication
and instrumentation systems. Frequency doubler is often made from analog multi-
pliers. However, Anuntahirunrat et al. [ 44 ] have demonstrated that by imposing
appropriate design conditions, the CCCIIs based circuit shown in Fig. 9.45 can
accomplish both these functions from the same structure.
It has been found [ 45 ] that an approximate expression for the output current of
this circuit is given by:
i out
k 5
ð
I DC þ
I 2 ˉ cos 2 ˉ
t
Þ
ð 9 : 61 Þ
1
R C 2 þ
k 5 ¼
k 4 V CC
ð
V EE
Þ
5 I 1 k 4 R S ;
k 4 ¼
ð
9
:
62
Þ
2 R x
I m
2 IðÞ
1
4 k 3
I DC
4 I 1 k 4 R S 1
þ
I 2 ˉ
I 1 R s K 3 K 4 ;
K 3 ¼
ð
9
:
63
Þ
;
2
From the above equations, it is clear that by appropriately selecting component
values and parameters, the circuit can generate a cosine wave of frequency two
ˉ
from an input current i x1 ¼
t derived from the input V m .
Siripruchyanun and Jaikla demonstrated in [ 45 ] that three CCCIIs are enough to
realize a current mode precision full wave rectifier with a couple of advantageous
features. Their preposition is shown in Fig. 9.46 .
The analysis of this circuit can be carried out by noting the following:
I m sin
ˉ
I con V T
4 I B 1 ;
v y 2 2 I B 2
v y 3 2 I B 3
V T
V y 2 ¼
V y 3 ¼
V x 1 ¼
R x 1 i x 1 ¼
i z 2 ¼
i z 3 ¼
ð
9
:
64
Þ
V T ;
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