Realization of Sinusoidal Oscillators Using CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 202

Frist

V 2

x

Second

y

Third

z CCII+

4

2

y

y

z

CCII+

CCII+ z

1

x 3

x

C 2

R 4

R 2

R 3

R 1

C 1

Fig. 7.14 VM two-phase quadrature oscillator proposed by Minhaj [ 49 ]

CCII−

y

CCII−

V 01

z

y

CCII−

V 02

x y

z

V 0n

C eq

R 2 z

x

R 1

x

R 2

C eq

C eq

R 1

R 2

R 1

Fig. 7.15 Generalized structure for realizing a multiphase oscillator proposed by Wu et al. [ 27 ]

Another three phase sinusoidal oscillator using only CCII+ s advanced by Skotis
and Psychalinos [ 52 ] is shown in Fig. 7.16 which is having in its internal structure a
cascade connection of two lossy non-inverting integrators, each made from a single
CCII+ and a lossy inverting integrator made from two CCII+ s.
A sample experimental result of the circuit from [ 54 ] obtained by using AD844
for realizing CCs and using component values as R 1 ¼ 10 K, R 2 ¼ 20 K, C ¼ 270 pF
with DC bias supply used for biasing AD844 as 10 V is shown in Fig. 7.16b .
While the measured value of the frequency has been found to be 45 KHz. That of
the phase difference was found to be 60 114 between V 02 and V 01 and

between V 03 and V 01 .
By addition of two inverting amplifies, each implemented from two resistors and
a CCII+, the circuit is readily converted into a six-phase quadrature oscillator as
shown in Fig. 7.17 .
The experimental results of the circuit from [ 54 ], as shown in Fig. 7.17b ,
demonstrate that by using AD844 for realizing CCs and using component values
as R 1 ¼ 10 K, R 2 ¼ 20 K, C ¼ 270 pF with DC bias supply used for biasing AD844

as 10 V, the measured value of the frequency has been found to be 46.9 KHz

whereas the measured phase difference was found to be 160 between V 01 / and V 01,

60 between V 02 and V 01 , 102 between V 02 / and V 01, 115 between V 03 and

V 01 and 56 between V 03 / and V 01.