Hardware Reference
In-Depth Information
s
2
C
1
R
1
C
2
R
2
1
R
a
2
þ
1
R
a
0
I
Notch
I
in
¼
provided that
R
b
2
R
b
0
R
a
0
R
a
2
¼
ð
6
:
53
Þ
;
Ds
ðÞ
s
2
C
1
R
1
C
2
R
2
1
R
a
2
s
R
a
1
C
1
R
1
1
þ
1
R
a
0
I
AP
I
in
¼
ð
6
:
54
Þ
Ds
ðÞ
provided that
R
b
2
R
b
0
R
b
1
R
a
2
¼
R
a
0
¼
R
a
1
and CCII+ connected with R
a1
should be replaced by
CCII
.
he filter configuration of Fig.
6.34
offers the controllability of its parameters by
independent grounded resistors and the CCII tracking errors were found [
28
]tobe
having insignificant effect on the performance of the realized filters and can be
precisely compensated [
28
].
The significant advantages of this configuration are the tunability of filter
parameters through separate grounded resistors and employment of grounded
capacitors as preferable from the view point of IC implementation.
6.2.3.7 MISO-Type Universal CM Biquads
We now present some exemplary MISO-type CM universal biquads from amongst
those existing in literature [
30
-
34
,
133
].
Ozcan, Cicekoglu and Kuntman Biquad A MISO-type CM filter employing a
single CCII+ along with only four passive components was presented by Ozcan
et al. in [
30
] and is shown in Fig.
6.35a
.
This configuration can realize the following filters:
i
out
1
C
1
C
2
R
2
R
1
Ds
s
C
2
R
1
Ds
i
out
i
2
¼
for i
1
¼
i
3
¼
0;
i
3
¼
for i
1
¼
i
2
¼
0 and
ðÞ
ðÞ
R
2
1
i
out
s
2
DðÞ
R
1
C
2
C
1
i
1
¼
; provided that i
2
¼
i
1
and
i
3
¼
i
1
þ
1
C
1
þ
1
R
2
1
C
2
1
C
1
C
2
R
1
R
2
s
2
where
Ds
ðÞ
¼
þ
s
þ
ð
6
:
55
Þ
Thus, the circuit realises LPF, BPF and HPF. Through RC:CR transformation HPF
can also be realized without any element matching condition.
The experimental results of this circuit designed for Butterworth characteristics
with gain ¼1, and pole frequency of 225 kHz with element values C
1
¼C
2
¼1 nF,
R
1
¼
12 V supply are
shown in Fig.
6.35b
, whereas a typical output waveform is shown in Fig.
6.35c
.
Very good correspondence between theoretical and experimental result has been
reported in [
30
]
1k
ʩ
,R
2
¼
500
ʩ
using AD844 to realize CCII+ biased with
Search WWH ::
Custom Search