Hardware Reference
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Fig. 5.40 Floating ideal
tunable FDNR simulation
scheme proposed by
Abdalla [
42
]
C
2
R
CCII
CCII
x
y
z
±
±
z
y
1
V
1
x
C
1
CCII
x
z
±
y
2
V
2
In 1987, Higashimura and Fukui [
53
] derived two new three-CC-based general-
ized floating immittance simulators based upon the nullor model shown in
Fig.
5.41
. Recalling that a CCII- is equivalent to a three terminal nullor, this
model leads to two possible realizations of the general floating immittances as
shown in Fig.
5.41b, c
respectively. Both the circuits simulate a floating impedance
between ports 1 and 2 having value of equivalent admittance as Y
1-2
¼
Y
1
Y
3
/Y
2
.
Higashimura and Fukui in another publication [
54
] during 1987, came up with
four new lossless tunable floating FDNR simulation circuits each using two CCIIs
and a current inversion type negative immittance convertor (NIC) as active ele-
ments. Needless to say, like all previously discussed circuits, these circuits also
have the advantage of not requiring any component matching conditions and
providing tunability of the FDNR value through a single variable resistor. These
circuits are shown in Fig.
5.42a-d
.
All the circuits of Fig.
5.42a-d
realize the admittance matrix:
,
D
0
¼
1
1
s
2
D
0
½
¼
Y
C
1
C
2
R
;
ð
5
:
48
Þ
11
It is interesting to point out that the same authors in [
48
] presented two more ideal
floating FDNR circuits, each employing two CCIIs, one inverting/non-inverting
buffer, two capacitors and a resistor. The circuit based upon inverting buffer,
therein however, will require two more equal-valued resistors if the inverting buffer
is implemented from a CCII or an op-amp.
5.3.8 Mixed-Source FIs Using CCIIs and Op-amps/OTAs
Recently, some researchers have also attempted to create floating inductance
configurations using CCs along with other building blocks like op-amps and
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