Analog Filter Design Revisited: Circuit Configurations Using Newer Varieties of CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 410

Fig. 12.43 VM universal
biquad proposed by Ghallab
et al. [ 122 ]

C 1

V 1

R 1 V y

OFCC

z-

V 2

y

z+

C 2

V 3

x

w

R 2

R w1

OFCC

V 0 z+

y

z-

x w

R w2

R 3

C 1 R 1 V 2 þ

V 3

s 2 V 1 þ

1 1

C 1 C 2 R 2 R 3

s

C 1 R 1

V 0 ¼ ð 12 : 153 Þ

1 1

C 1 C 2 R 2 R 3

s 2 þ s þ

From the above equation, all the second-order standard filter responses can be
obtained subject to the following conditions:
HPF: if V 2 ¼

V 3 ¼ 0 (grounded) and V 1 ¼ V in (input signal); BPF: if V 1 ¼ V 3 ¼ 0

and V 2 ¼ V in ; LPF: if V 1 ¼ V 2 ¼ 0 and V 3 ¼ V in ; Notch: if V 2 ¼ 0 and V 1 ¼ V 3 ¼ V in

and APF: if V 1 ¼ V 2 ¼ V 3 ¼ V in

The filter parameters ω 0 and Q 0 can be obtained as:

s

C 1

r

1
C 1 C 2 R 2 R 3

C 2 R 3 R 2

ω 0 ¼ and Q 0 ¼ R 1 ð 12 : 154 Þ

From the above equation ( 12.154 ), it is clear that ω 0 can be varied by R 2 or R 3 and

Q 0 can be tuned by the ratio R 1 /R 2 ,R 1 /R 3 or C 1 /C 2 . Hence, both ω 0 and Q 0 are

orthogonally controllable.