Systematic realisation of quadrature oscillators using current differencing buffered amplifiers

A systematic approach is presented to realise quadrature oscillators using current differencing buffered amplifiers (CDBAs). Based on a general scheme employing a cascade of a special type of low-pass filter and an integrator in a closed loop, a general configuration is formulated that yields 12 single-resistor-controlled-quadrature oscillator circuits using CDBAs an active elements. All the oscillator circuits enjoy fully uncoupled independent control of condition of oscillation and frequency of oscillation using a minimum possible number of active components, grounded/virtually grounded capacitors and grounded/virtually grounded resistors. PSPICE simulation results along with hardware experimental results, based on commercially available AD844 ICs to construct the CDBAs, are included which confirm the practical workability of the new quadrature oscillator configurations.