By S. S. Gupta and Rai Senani' Abstract This paper presents a catalogue of single resistance controlled oscillators employing all grounded passive elements realized by using a recently introduced active building block called 'differential difference complementary current conveyor (DDCCC)'. The circuits employ two DDCCCs, two grounded capacitors and three grounded resistors. These circuits offer the following novel features: (i) employment of a minimum number of (five) passive elements (all of which are grounded) using only one kind of active elements (ii) availability of the intended single-resistance-control of frequency even under the influence of parasitics without affecting the condition of oscillation which is also independently adjustable and, (ii i) availability of current mode output(s) explicitly. Results of non-ideal analysis of circuits incorporating various parasitics have been included, workability of the derived circuits has been established by PSPICE simulations and based upon these, the best circuits of this catalogue have been identified.

Realisation of current-mode srcos using all grounded passive elements

New types of variable frequency sinewave oscillators are introduced which bring the most desirable linear tuning laws of the forms fo ? Re, and fo ? Ce into the domain of sinusoidal oscillators. Two exemplary circuits are presented and the experimental results are given which are found to be in agreement with the theory. In their various modes of operation, the proposed types of oscillators promise to provide many significant advantages in various instrumentation and measurement applications which are not possible to achieve with previously known active resistance-capacitance (RC) oscillators.

New Types of Sinewave Oscillators

A comprehensive study for generation and design of grounded-capacitor variable-frequency RC-active oscillators using operational amplifiers (OAs) is reported. All the circuits derived are canonic, that is, the number of components (active as well as passive) in them is a minimum. First, a set of eight canonic circuits is found, each using one OA, two capacitors and six resistors. However, these circuits suffer from either a poor start-up property or a limited frequency range of variation. Thus, based on this set of eight circuits, another set of 12 variable-frequency oscillators is derived. This set provides easy tunability and a wider tuning range. Both the sets are shown to be complete. All the variable-frequency oscillators are single resistor controlled. Two of the circuits have their variable resistors grounded which makes them attractive candidates for voltage-controlled oscillators. Design equations for all the oscillator circuits are given. All the circuits have been laboratory tested. Experimental results are found to be in close agreement with the theoretical analysis. Representative test results are included in the article.

Erratum: Generation and design of canonic grounded capacitor variable frequency RC-active oscillators

A novel sinusoidal oscillator is presented which employs only one operational amplifier, two capacitors, and six resistors and has the facility of independent control of oscillation frequency through a single grounded resistor. The circuit may also be used as a very-low-frequency oscillator and as an economical voltage-controlled oscillator.

New canonic sinusoidal oscillator with independent frequency control through a single grounded resistor

A transconductance-amplifier-capacitor sinusoidal oscillator is introduced. The circuit requires only two operational transconductance amplifiers (OTAs) and two grounded capacitors. The frequency of oscillation is linearly tunable over a wide frequency range. >

A new minimum component active-C OTA-based linear voltage (current)-controlled sinusoidal oscillator

A simple voltage controlled oscillator circuit using capacitors, all of which are grounded, is presented. The circuit is thus attractive from the point of view of monolithic or hybrid IC fabrication. The frequency of oscillation can be varied over a wide range, with the amplitude of oscillation remaining relatively stable over the range. Experimental results are given that agree closely with the theoretical predictions.

B.B. Bhattacharyya

Papers

A simple voltage controlled oscillator with grounded capacitors