VDTA-based Orthogonally and Electronically Controllable Mixed Mode Third-Order Quadrature Oscillator

This paper presents a novel electronically controllable third-order mixed mode quadrature oscillator that employs voltage differencing transconductance amplifier (VDTA) as the active building block. The proposed design employs two VDTAs, three grounded capacitors and a single grounded resistor. The use of grounded passive components provides the integrability support to the proposed circuit. It enjoys the most desirable characteristics of orthogonal control of frequency of oscillation and oscillation condition. Also the proposed quadrature oscillator generates both current and voltage waveforms at the output. The oscillator performs admirably and all the theoretical results are confirmed by the PSPICE simulations with $0.18 \mu\text{m}$ TSMC technology process parameters.