Realization of tunable pole-Q current-mode OTA-C universal filter

A realization of a current-mode operational transconductance amplifiercapacitor (OTA-C) universal filter with tunable pole-Q is proposed. A biquadratic band-reject function is used as the initial synthesis function based on three integrator blocks. Consequently, the proposed filter uses a total of three multiple-output OTAs and three grounded capacitors. Five types of transfer functions, namely, low-pass, high-pass, band-pass, band-reject, and all-pass responses, can be obtained without changing the circuit topology. The pole-Q (Q0) and the pole-frequency (?0) parameters are independently tuned. The Q0 and ?0 parameters are electronically tuned by adjusting the transconductance gains of the OTAs. Furthermore, Q0 can be tuned by varying the capacitor manually without affecting ?0. SPICE simulation results of the proposed filter are presented. © Springer Science+Business Media, LLC 2010.