Tunable current-mode quadrature oscillator using CFTAs and grounded capacitors

In this paper, an electronically tunable current-mode quadrature oscillator employing three current follower trans-conductance amplifiers (CFTAs) and two grounded capacitors is proposed. The use of all grounded capacitors makes the proposed circuit ideal for integrated circuit implementation. The circuit provides two high-output impedance current signals with 90° phase difference. It condition of oscillation (CO) and frequency of oscillation (FO) can be adjusted independently and electronically. The active and passive sensitivities of the proposed configuration are low. PSPICE simulation results using TSMC 0.25 μm CMOS process parameters are given to prove the theory.