Hardware Reference
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C
1
C
2
DO-DDCC
DO-DDCC
DO-DDCC
z
2
z
2
z
1
y
1
y
1
+
-
y
1
y
2
y
3
V
in
2
y
2
y
2
3
1
y
3
z
1
y
3
z
1
z
2
x
x
x
+
-
+
-
+
-
V
LP
V
BP
V
HP
R
5
R
3
R
2
R
1
R
4
Fig. 12.21 DO-DDCC based differential VM KHN biquad proposed by Ibrahim and Kuntman
(Adapted from [
34
]
2004 Elsevier)
©
R
5
C
1
R
1
R
2
R
5
C
1
C
2
R
1
R
2
R
3
s
2
Ds
ðÞ¼
þ
s
þ
ð
12
:
80
Þ
The filter parameters
ˉ
0
and Q
0
are orthogonally tunable and are given by:
r
R
5
C
1
C
2
R
1
R
2
R
3
r
C
1
R
1
R
2
R
5
R
3
C
2
ω
0
¼
and Q
0
¼
ð
12
:
81
Þ
Lee
'
s mixed-mode biquad A mixed-mode fully cascadable universal biquad filter
configuration was proposed by Lee [
51
] in 2011 employing three DDCCs, two
grounded capacitors and three grounded resistors. The presented structure is capa-
ble of providing inverting, non-inverting and differential types all standard filter
responses from the same topology and is suitable for cascading in all four possible
modes.
Assuming ideal DDCCs, a routine analysis of the circuit of Fig.
12.22
, yields:
N
1
s
ðÞ=
R
2
þ
N
3
s
ðÞ
I
out
¼
ð
12
:
82
Þ
Ds
ðÞ
and
V
out
¼
N
1
s
ðÞþ
N
2
s
ðÞ
R
2
ð
12
:
83
Þ
Ds
ðÞ
where
s
2
C
1
C
2
V
in
1
N
1
s
ðÞ¼
ð
V
in
2
Þ
sC
1
V
in
3
ð
V
in
4
Þ=
R
1
þ
ð
V
in
5
V
in
6
Þ=
R
1
R
3
,
ð
12
:
84
Þ
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