Electronically Tunable Current-Mode Quadrature Oscillator Derived from First-Order Allpass Filter

In this study, an electronic controllability current-mode quadrature oscillator based on first-order all pass filter employing current follower cascaded Tran conductance amplifier (CFCTA) is presented. The proposed oscillator uses two CFCTAs, two electronic resistors and two grounded capacitor, which is easier for monolithic IC implementation. The condition of oscillation (CO) and frequency of oscillation are electronically and independently controlled which is well suited to use in modern electronic devices controlled by microprocessor. Moreover, the oscillator possesses high output impedances and thus it enables simple current-mode cascading. The PSPICE simulation results are included, verifying the workability of the proposed current-mode oscillator. The given results agree well with the theoretical anticipation.