Sinusoidal Oscillator Realizations Using Other Types of Current Conveyors - Current Conveyors: Variants, Applications and Hardware Implementations - page 442

Out of the two SRCO versions, version (i) uses a minimum number of capacitors
(two) and four resistors while version (ii) employs four capacitors and two resistors.
Thus, version (i) of SRCO is superior as compared to version (ii), although both the
oscillators qualify for obtaining fully-uncoupled condition of oscillation and fre-
quency of oscillation.
The workability of he circuits described has been verified by using the CMOS
ICCII from [ 54 ] using 1.2

μ

m CMOS process model parameters used in SPICE
simulations with component values designed to achieve an oscillation frequency of
39.78 KHz while the CMOS ICCII was biased with 2.5 V DC power supplies.
The frequency generated by SPICE simulations was found to be 38.76 KHz which
is seen to be in excellent agreement with theory.

13.5 Explicit Current Output (ECO) SRCO Using All
Grounded Passive Components

A DDCC has already been introduced in an earlier chapter. If we combine DDCC
+ and DDCC- into a single unit it can be called a differential difference compli-
mentary current conveyor (DDCCC). It was shown by Gupta and Senani in [ 9 ] that
a DDCCC is a versatile building block to implement an explicit current output
SRCO as shown here in Fig. 13.4 which employs two DDCCCs and five passive
elements (three resistors and two capacitors) all of which are grounded.
The CO and FO for this circuit are given by:

R 1 R 3 ð 13 : 10 Þ

1

f 0 ¼ p

C 1 C 2 R 2 R 3

ð 13 : 11 Þ

ˀ

2

Thus, CO is controllable by R 1 while FO is controllable independently by R 2 .
The feasibility of the circuit of Fig. 13.4 was confirmed by the DVCC circuit of
[ 53 ] and modifying it to become a DDCCC by creating an extra complementary
Z-output. The variation of oscillation frequency with the resistor R 2 exhibited an
excellent correspondence with the theoretical plot thereby establishing the correct-
ness of the formulation.
For a fixed-frequency sinusoidal oscillator with all grounded elements and
providing an ECO, see [ 48 ] whereas for a number of other ECO oscillators using
Transconductance second generation Current Conveyor (TCCII), Generalized Cur-
rent Conveyor (GCC) and second generation Controlled Current Conveyor (CCCII)
can be found in [ 3 , 12 , 31 ] respectively.