Electronically Tunable Current-Mode Universal Filter Employing CCCIIs and Grounded Capacitors

This paper introduces an electronically tunable current-mode universal biquadratic filter using second generation current controlled conveyors (CCCIIs). The filter circuit is constructed with a CCCII, three dual current output CCCIIs (DO-CCCIIs) and two grounded capacitors. The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by choosing appropriate current output branches without any component matching conditions. Additionally, the circuit parameters can be tuned orthogonally by adjusting the bias currents of the CCCIIs. The biquadratic filter enjoys very low sensitivities with respect to the circuit active and passive components. Some examples are given together with simulated results by PSPICE