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obtained by extending the four-transistor mixed-translinear-cell by adding two
more transistors to create an additional terminal and using simple current mirrors
to create the second Z terminal.
It needs further investigation to see which other applications in analog signal
processing can be effectively realized using the TXTZ-CCII building blocks.
10.2.24 Differential CCII
A differential Current Conveyor (DCCII) [
64
,
65
] is another special type of CC
which has two X-terminals X
p
and X
n
at both of which the same voltage appears as
applied on the Y-terminal. The Y terminal being a voltage input terminal has I
y
¼
0.
The output current in the terminal Z is difference of the two currents applied to the
X-terminals X
p
and X
n
. Thus, a DCCII is a four-port characterized by:
0
@
1
A
¼
0
@
1
A
0
@
1
A
I
Y
V
xp
V
xn
I
Z
0000
1000
1000
01
V
Y
I
Xp
I
xn
V
Z
ð
10
:
24
Þ
10
The symbolic notation of the DCCII and its exemplary CMOS implementation is
shown in Fig.
10.25
.
The proposers of the DCCII have demonstrated its use in realizing a fist order all
pass filter, however, the full potential of the DCCII as made available due to its
useful current differencing property coupled with its relatively simple internal
circuit architecture, does not appear to have been fully exploited yet.
10.2.25 Universal Voltage Conveyor
The concept of an n-port voltage conveyor (VC) was introduced by Cajka and Vrba
in 2004 [
47
,
48
]. In an n-port VC, the driving quantity is the independent voltage V
x
applied to the input port X. This independent voltage V
x
is
conveyed
to the output
ports Z
1
,Z
2
......
..Z
n
with the
polarities. It has a number of auxiliary ports
Y
n
, on which one can apply
n
number of independent
node current inputs called I
y1
,I
y2
...
labeled as Y
1
,Y
2
......
I
yn
(Fig.
10.26
).
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