Analog Filter Design Revisited: Circuit Configurations Using Newer Varieties of CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 387

V BP

I B1 I B2 I B3

y 3 y 1 y 1

z

z z

1 2 3

y 2 DDCCTA
y 3

V in

y 1

C 1

y 2 DDCCTA
y 3

DDCCTA

y 2

O O O

x x

x

V BS V AP

V LP

V HP

C 2

Fig. 12.23 DDCCTA-based resistorless universal filter proposed by Tangsrirat et al. (Adapted
from [ 65 ] 2013 Elsevier)

©

s 2
Ds

V LP
V in ¼

ð g m 1 g m 2 = C 1 C 2 Þ V HP

V in ¼

V BP

V in ¼

sg m 2 = ð C 1 Þ

ð 12 : 89 Þ

;

ðÞ ;

Ds ðÞ Ds ðÞ

s 2

V AP
V in ¼

sg m 2 = ð C 1 Þþ ð g m 1 g m 2 = C 1 C 2 Þ

ð 12 : 90 Þ

Ds ðÞ

and

s 2 V Notch

V in ¼

þ ð g m 1 g m 2 = C 1 C 2 Þ

ð 12 : 91 Þ

Ds ðÞ

where

s 2 Ds ðÞ¼ þ sg m 2 = ð C 1 Þþ ð g m 1 g m 2 = C 1 C 2 Þ ð 12 : 92 Þ

The values of filter parameters ˉ 0 and Q 0 can be given by:

s

C 1 g m 1
g m 2 C 2

r

g m 1 g m 2
C 1 C 2

ω 0 ¼ andQ 0 ¼ ð 12 : 93 Þ

Thus, ˉ 0 can be controlled electronically by varying g m1 and g m2 simultaneously

while maintaining the ratio of g m1 /g m2 constant.