Realization of Sinusoidal Oscillators Using CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 203

a

V 01

y

V 02

CCII+ z y

V 03

x z y

CCII+

R 2

C

x

R 2

CCII+

z

x

R 1

CCII+

z

x
R 1

C

R 2

R 1 C y

R 2

b

Fig. 7.16 Realization of three-phase oscillator employing CCII + s proposed by Skotis and
Psychalinos (Adapted from [ 52 ] © 2009 Elsevier GmbH) (a) The circuit (b) Typical waveforms

Both the circuits follow essentially from the general block diagram of Fig. 7.18
which shows the basic principle of synthesizing an n-phase oscillator for

being
odd or even. The second circuit then follows from this schematic by adding two
inverting amplifiers.
By a straight forward analysis, the open loop transfer function assuming

n

' '

n

' '

identical stages is given by:

n

K

Ls ðÞ¼ ð 7 : 38 Þ

1 þ s ˄

Denoting the maximum gain (R 2 /R 1 ) as K of non-inverting lossy integrators and the
time constant CR 2 ¼ ˄

, the criterion of oscillation at a specific frequency ˉ 0 requires

the following conditions to be fulfilled:

ω 0 tan n

1

˄ ¼ ð 7 : 39 Þ