An active-only high output-impedance current-mode universal biquad filter and quadrature oscillator based on lossless differentiators

This article presents a novel circuit, which can function both a high-output impedance current-mode universal biquad filter and quadrature sinusoidal oscillator for the same topology. The features of the proposed circuit as a universal filter are that the pole frequency and the quality factor can be adjusted independently controlled via input bias current. Besides performing as a universal filter, with an appropriate condition, the proposed circuit can function as a quadrature oscillator without changing its circuit topology. The oscillation frequency and oscillation condition can be independently controlled via input bias currents. In addition, since the proposed circuit comprises only active elements, which are 3 CCCCTAs and 2 operational amplifiers (OAs), it is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted.