Electronically tunable current-mode quadrature oscillator using current differencing transconductance amplifiers

A new electronically tunable single-element-controlled current-mode quadrature oscillator circuit using current differencing transconductance amplifiers (CDTAs) is presented. The proposed oscillator is consisted of two CDTAs, two grounded capacitors and one grounded resistor, which is beneficial to monolithic integrated circuit implementation. The oscillation condition and oscillation frequency of the circuit are independently controllable. Also, the oscillation frequency can be controlled by a bias current of CDTA. The realized of the circuit provides four quadrature current outputs at high output impedance nodes. PSPICE simulation results that confirm the theoretical predictions are given. © 2009 IEEE.