Realization of Sinusoidal Oscillators Using CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 197

y

x

y CCII+ z

R 1

z CCII+ CCI−

z

x
R 3

C 1

y

x

C 2

R 2

Fig. 7.9 SRCO employing AGPE proposed by Chang [ 17 ]

the amplitude of such oscillators wherein this condition setting grounded resistor can
also be replace by a grounded VCR as part of the feedback control circuit.
In the literature several CC-based oscillators have been reported which employ
all grounded passive elements (AGPE), for instance, [ 17 , 22 , 25 , 26 , 28 - 30 , 32 , 37 ,
46 , 50 , 53 , 57 ]. In the following we discuss some exemplary circuits out of these.
A circuit which although requires three CCs and does not have the advantage of
providing a buffered outlet but has the advantage of employing all grounded passive
elements (AGPE) was proposed by Chang [ 17 ] and is shown in Fig. 7.9 .
The circuit is characterized by the following CO and FO:

CO R 1 ¼ R 3 ð 7 : 26 Þ

:

r

1
C 1 C 2 R 2 R 3

FO

: ω 0 ¼

ð 7 : 27 Þ

One of the drawbacks of the circuit of Chang (use of three CCs) described above
was overcome by Liu in [ 22 ] who came up with a novel configuration which could
achieve all the features of Chang s circuit while employing only two CCs. This

circuit is shown in Fig. 7.10 and is characterized by

'

CO R 1 ¼ R 3 ð 7 : 28 Þ

:

r

1
C 1 C 2 R 1 R 2

FO

: ω 0 ¼

ð 7 : 29 Þ

This circuit lets the control of CO through R 3 and that of FO by R 2 . Also, the circuit
enjoys very good frequency stability properties since the frequency stability factor
is found to be as S F 2 p which can be made quite large by making the resistor

ratio n large as in the circuit of [ 18 ].
Another similar circuit with five grounded passive elements and using both CCI-
was advanced by Abuelma

atti and Al-Ghumaiz in [ 28 ] and is shown in Fig. 7.11 .
This circuit is characterized by CO and FO which are as follows:-

'

r

1
C 1 C 2 R 2 R 3

R 1 ¼ R 2 ;

: ω 0 ¼

ð : Þ

CO : FO 7 30