Universal voltage-mode filter with three inputs and one output using three current conveyors and one voltage follower

A universal voltage-mode second-order filter with three inputs and one output employing three current conveyors, one voltage-follower, two capacitors and three resistors is presented. The proposed circuit offers the following advantageous features: realisation of allpass, notch, highpass, bandpass and lowpass signals from the same configuration, no requirements for component-matching conditions, orthogonal control of ω_o and Q, low active and passive sensitivities and cascadability