A simple sinusoidal quadrature oscillator using a single active element

Abstract

This study describes a simple design for a single active element sinusoidal oscillator with a quadrature signal. A current conveyor transconductance amplifier (CCTA), a single resistor, and two grounded capacitors are used in the first circuit. The second circuit is improved by using a current-controlled current conveyor transconductance amplifier (CCCCTA) and two grounded capacitors without a passive resistor, which means the grounded capacitor is suitably implemented for the IC fabrication. The oscillation condition and frequency of both circuits can be controlled using the same method that concurrently adjusts the DC bias current and the resistance as well as the oscillation frequency can be independently adjusted by capacitances. The CCTA is achieved by cascading the integrated circuits (IC) AD844 and LM13700, made by Analog Devices Corporation and Texas Instruments, respectively, which are available for commercial purchase. The sinusoidal quadrature signals in the time-domain and frequency-domain can be shown with computer simulations and the results of experiments. The Monte Carlo Analysis is also utilized to examine the oscillation frequency with the influence of passive element tolerance errors. The predicted oscillation frequency has a standard variation of about 20.04 kHz, with a maximum frequency of approximately 346.89 kHz and a minimum frequency of approximately 259.09 kHz. In addition, the mean and median frequencies are 296.10 and 293.98 kHz, respectively. The results of this study indicate that computer simulation and experiment are similar to a theoretical analysis, making them suiTable for use in the teaching of electrical and electronic engineering