First, Second and Higher Order Filter Design Using Current Conveyors - Current Conveyors: Variants, Applications and Hardware Implementations - page 159

R 2

C 2

CCII-4

y

z

x

I in C 1

R 1

y

x

x y y

x

CCII+3

CCII+2 +

z

CCII+1

z

z

I 03

I 01

I 02

Fig. 6.26 CM universal biquadratic filter proposed by Ozoguz and Acar [ 22 ]

V a

CCII+

I 0k

y
x

CCII+1 z

y

z

Y k

x

CCII+

I 01 y

x

Y c Y b

V b

z

CCII-I

Y 1

x

z

y

CCII+

I 0m

I bias

y

Y a

V c

z

x

Y d

Y m

CCII+

I 0n

y

V d z

x

Y n

Fig. 6.27 CC-based CM universal filter with single input and four outputs proposed by
Abuelma ' atti and Shabra (Adapted from [ 23 ] © 1996 Elsevier Science Limited)

This circuit, therefore, is an excellent vehicle for generating CM universal
biquads by replacing the inductor by CC-simulated inductor and then realizing
the remaining two functions namely, notch and APF by adding LPF and HPF
currents in the former case and by adding LPF, inverting BPF and HPF currents
in the latter case.
The five transfer functions, thus, realizable, are given by: