First, Second and Higher Order Filter Design Using Current Conveyors - Current Conveyors: Variants, Applications and Hardware Implementations - page 163

R 1

I in

y
x CCII−

z

y

y
CCII−

z

C 2

CCII−
x

z

R 4

C 1

R 5

R 3

y

z

CCII+

x y y

z

z

R 2

CCII+ CCII+

x I low

x

I band

R 7

R 8

y

z

CCII+
x

I high

R 6

Fig. 6.32 CCII-based CM universal biquad proposed by Chang [ 26 ]

R 6

s 2 R 1

R 1
R 4 R 5 R 3 C 1 C 2
Ds

þ

I notch
I i ¼

for R 8 ¼ R 3 : ð 6 : 45 Þ

ðÞ

þ

R 1
C 2 R 2 R 4

R 1
R 4 R 5 R 3 C 1 C 2

s 2 s

I all

I i ¼

for R 6 ¼ R 1 ,R 7 ¼ R 2 and R 8 ¼ R 3

Ds ðÞ

s R 1

R 1
C 1 C 2 R 3 R 4 R 5

s 2 where Ds ðÞ ¼ þ

C 2 R 2 R 4 þ

ð 6 : 46 Þ

This circuit provides all the advantages of the earlier circuit by Senani [ 25 ] and in
addition has the advantages of (i) employing active elements of the same type: only
CCIIs (ii) tunable current gain and (iii) independent control of ω 0 ,Q 0 and current
gain through separate resistors in all the five responses.
The above mentioned aspects were verified by bread boarded implementations
of the circuit where CCIIs were realized by LF 356 N type op-amps and CA
3096AE type mixed-transistor arrays used for implementing current mirrors for
op-amps engaged in supply current sensing mode.

Chang ' s five CC Universal CM Biquad Another CM biquad was presented by
Chang in [ 27 ] which had single input and three outputs and employed five CCs,
three grounded resistors and two grounded capacitors as shown in Fig. 6.33 .

This filter structure too realizes all the five second-order filter functions without
the requirement of critical component matching/cancellation constraints and offers