Current-mode Active-only Universal Filter

A universal current-mode active-only filter using the biquadratic transfer function is proposed. The proposed circuit is realized by minimized active-only components count without external passive elements. The different kinds of filter function as lowpass, highpass, bandpass and band-reject response can be obtained without changing circuit topology. The proposed circuit is realized by using MOS transistors, OTAs, and op amps. The parameters omega_P can be electronically tuned through adjusting the transconductance gains of the OTA and Q_P can be tuned by changing of their components without effect to omega_P. The simulation results are given by PSpice