Universal two-input two-output current-mode active biquad using FTFNs

A universal active biquad using the four-terminal floating nullors (FTFNs) is presented. The proposed circuit uses two FTFNs, two capacitors and two resistors. The proposed circuit has two input currents and can provide two highimpedance output currents. Without changing the circuit topology, the output currents can realize lowpass, highpass, bandpass, and allpass transfer functions. A notch transfer function can be obtained by adding a voltage-to-current converter using an additional FTFN. The proposed circuit enjoys low passive sensitivities and orthogonal tuning of the parameters ω_o and ω_o/Q_o.