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I
01
+
Y
I
02
V
out
Z
Y
Z
X
+
CCCII
1
R
c1
V
in
X
−
CCCII
2
R
c2
R
eq
−
Fig. 9.50 A square rooting circuit proposed by Dejhan and Netbut [
49
], Netbut et al. [
50
]
+V
CC
V
in
I
in
Q
R2
Q
R1
I
in
R
eq
I
eq
V
in
Q
R3
Q
R4
I
eq
−V
EE
Fig. 9.51 A current-controlled resistance [
49
,
50
]
A square rooter in CM was also proposed by Dejhan and Netbut in [
49
] and in
[
50
] by Netbut et al.. This circuit is shown in Fig.
9.52
. The expression for the
output current of this circuit is given by:
p
I
01
p
I
in
I
out
¼
ð
9
:
75
Þ
Thus, the circuit of Fig.
9.52
yields the output current which is square-root of the
input current signal.
It is interesting to note that while the performance of the VM circuits is
temperature dependent that of the CM circuits is temperature independent. Further-
more it can be seen that out of the two circuits the CM square rooter can be realized
exclusively by bipolar transistors and hence more suitable for IC implementation.
The workability of both the structures has however being established by SPICE
simulation results using BJTs PR100N and NR 100N. It has been shown that the
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