Voltage-mode universal biquadratic filter and quadrature oscillator using CFAs

The paper presents a new voltage-mode universal biquadratic filter and a new quadrature oscillator using two current-feedback amplifiers (CFAs) with two capacitors and three resistors. The proposed circuit can work as both a voltage-mode universal biquadratic filter and a quadrature oscillator without changing the circuit configuration. As a voltage-mode universal biquadratic filter, the proposed circuit can be easily realized all five generic filtering functions by selecting three different input voltage signals. The proposed filter allows the orthogonal controllability of the quality factor and the resonance angular frequency. If there is no input voltage signal, the proposed configuration can work as a quadrature oscillator without changing the circuit topology. This proposed topology provides two quadrature voltage outputs. The oscillation condition and oscillation frequency are also independent adjustability. The experimental results show that the new voltage-mode universal biquadratic filter and quadrature oscillator are feasible.