Electronically Tunable Voltage-Mode Universal Filter with One Input and Four Outputs Using Seven OTAs and Two Grounded Capacitors

This paper presents a new electronically tunable voltage-mode universal biquadratic filter with single input and four outputs employing seven operational transconductance amplifiers and two grounded capacitors. The use of grounded capacitor makes the circuit ideal for integrated circuit implementation. The proposed filter can realize voltage-mode low-pass, band-pass, high-pass and band-stop filter responses without both component-matching condition requirement and inverting-type input signal requirement. High input impedance is possessed which can be directly connected in cascadability to implement high-order filter. The natural frequency and the quality factor can be orthogonally controlled. Also the natural frequency and quality factor can be electronically tuned. The active and passive sensitivities of the circuit are low. The workability of the proposed filter is confirmed by PSPICE simulator. From simulation results, it can be expressed that the proposed circuit agrees well with theory.