A voltage/current controlled oscillator using OTAs and RS Flip Flop

This paper presents an electronic oscillator specially designed to be controlled in oscillation frequency by the control voltage and external bias current signals. The realization technique is simple and inexpensive based on the use of commercial available devices. The proposed circuit consists of operational transconductance amplifiers (OTAs) and an RS flip flop to generate tunable sawtooth and square waves. Experimental results verifying the performances of the proposed circuit are in close agreement with the expected values. An application example showing the usefulness of the proposed voltage controlled oscillator in phase-locked loop frequency synthesizer is also introduced.