Triple-Input Single-Output Electronically Controlled Voltage-Mode Biquadratic Filter

This article presents the possibility of realizing a voltage-mode biquadratic filter having with three input terminals and single output terminal. The circuit employing only two voltage differencing gain amplifiers (VDGAs) together with two capacitors can realize all the five standard biquadratic filter functions at a single low-impedance-output terminal. It also provides orthogonal current tuning of the natural angular frequency ( ωo) and the quality factor ( Q), and has low active and passive element sensitivities. To confirm the theory, simulation results using PSPICE software are accomplished.