Analog Filter Design Revisited: Circuit Configurations Using Newer Varieties of CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 367

R 4

z 1

y 1
y 2

V 05 1

V 03

V 01

R 3

DVCC

V i1 z 1

z 2 y 1 V 02

x

2

V 04

V i3

DVCC

z 2

y 2

x C 2

R 1

C 1

V i2

R 2

Fig. 12.5 VM biquad filter using two DVCCs proposed by Chen and Shen [ 6 ]

h V i 1 þ n

þ

o V i 2 n

þ

V i 3 o i

R 1 R 2 R 3

s 2 C 1 C 2

1
R 3

1
R 1 R 2

1

s 2 C 1 C 2

1
R 2

1
R 2 R 3

sC 2 sC 1

V 04 ¼

DðÞ

ð 12 : 14 Þ

h

R 3 V i 1 þ

n

R 2 R 2 R 3 V i 3

o i

s 2 C 1 C 2

1

ð V i 2 Þ s 2 C 1 C 2

1

þ sC 1

1

R 4
R 1

V 05 ¼

Ds ðÞ

ð : Þ

12 15

þ þ

1
R 3

1
R 1 R 2

1
R 1 R 2 R 3

s 2 C 1 C 2 where D s ðÞ¼ sC 2 ð 12 : 16 Þ

Depending upon the appropriate choice(s) of the input signal(s), the various filter
responses can be obtained through the following two cases:

Case I
(a) If we choose V i2 ¼ V i3 ¼ 0 and V i1 ¼ V in ¼ input signal, then the following

filter functions can be obtained:

R 1 R 3
Ds

R 1 R 2 R 3
Ds

n

R 3

o

1 1

s 2 C 1 C 2

1 1

R 1 R 2 R 3

sC 2 þ

V 01
V in ¼

V 02
V in ¼

V 03
V in ¼

V 04
V in

;

ðÞ ;

;

ðÞ Ds ðÞ

R 3
Ds

R 3
Ds

s 2 C 1 C 2

1

s 2 C 1 C 2

1

and V 05

R 4
R 1

¼

V in ¼

ð 12 : 17 Þ

ðÞ ðÞ

Thus, from the above equations, it is clear that a BPF, LPF, and notch can be
realized at V 01 ,V 02 , and V 03 respectively while two HPF functions can be obtained
at V 04 and V 05 respectively.