High input impedance capacitor-grounded voltage-mode universal filter with three-input three-output using single-ended OTAs

This paper presents a new voltage-mode three-input three-output universal filter using single-ended operational transconductance amplifiers (OTAs) and grounded capacitors. The circuit provides low-pass, high-pass, band-pass, band-stop and all-pass voltage responses at a high impedance input terminal, which enable easy cascadability. The natural frequency (ω_o) and the quality factor can be controlled orthogonally by setting the circuit components. The parameter ω_o can also be controlled electronically by adjusting the biasing currents of OTAs. No critical component-matching conditions and no inverting-type input signals are required for realizing all the filter responses. Simulation results are performed to confirm the theoretical analysis.