Electronically tunable capacitor-grounded voltage-mode universal filter with four-input one-output using single-ended OTAs

This paper presents a new four inputs and one output voltage-mode universal filter using single-ended operational transconductance amplifiers (OTAs) and grounded capacitors. By appropriately connecting the input terminals, the proposed circuit can provide low-pass, band-pass, high-pass, band-stop and all-pass voltage responses. The filter also offers an orthogonal control of the natural frequency and the quality factor by adjusting the biasing currents of OTAs. The performances of the proposed filter are simulated with PSPICE to confirm the presented theory.