A Novel Current-Mode Alternative Topology for Realization of Universal Filter and Quadrature Oscillator

Abstract- In this article, a new topology which can function both as quadrature oscillator and universal biquad filter is introduced. Working as quadrature oscillator, the oscillation condition and oscillation frequency can be adjusted independently. Functioning as universal biquad filter, it can provide 3 standard functions (Highpass, Lowpass, Bandpass), the quality factor and cutoff frequency can be tuned orthogonally. It comprises 2 voltage to current converters, 2 grounded capacitors, 1 positive grounded and 1 negative grounded resistors. The proposed topology can work as either quadrature oscillator or biquad filter without changing circuit topology. In addition, it can provide output signal both in current-mode and voltage-mode simultaneously. The current-mode universal filter and quadrature oscillator using OTAs being active elements as an example are proposed to shown the usefulness of proposed topology and the PSPICE simulation results are depicted. The given results agree well with the theoretical anticipations. Index Terms- universal filter, OTA, current-mode, quadrature oscillator, topolog