Hardware Reference
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R 1
C 1
x
CCII+
V 0
z
R 4
C 2
y
Y in
R 3
R 2
Fig. 7.2 A canonic active-RC circuit capable of realizing an ideal FDNR, a lossy FDNR, parallel
tuned circuit and an oscilltor proposed by Soliman [ 4 ]
If the component values are selected such that R 1 ¼
R 3 ,R 2 ¼
2R 1 ,R 1 >
R 4 and
C 2 ¼
(3/2)C 1 , then
s
1
3
1
1
R 1
R 4
f 0 ¼
ð
7
:
6
Þ
ˀ
C 1 R 1
2
Thus, it is seen that f o can be controlled by a single grounded resistance R 4 and can
also be controlled by external voltage by replacing this resistor by an FET working
in the triode region, however, the circuit lacks the provisions of providing inde-
pendent control of CO through a single variable resistance.
Another single-CC SRCO which does not have the above mentioned limitation
was proposed by Senani in [ 5 ]. This circuit employs one more resistor than
Soliman ' s circuit and is shown here as Fig. 7.3 . Subject to the fulfillment of the
condition
C 1
C 2 ¼ 1 þ
1
R 1 þ
1
R 2
R 3
ð 7 : 7 Þ
the characterizations of this circuit are:
CO
R 4 ¼
R 2
ð
7
:
8
Þ
:
1 = 2
R 2
2 C 1 C 2 R 1 R 3 R 0
FO
: ω 0 ¼
ð
7
:
9
Þ
It is, thus, seen that in this circuit, CO can be satisfied by adjusting the grounded
resistor R 4 without effecting FO which is also independently controllable by
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