New OTA-C Current-mode Comb Filter

Abstract: A new circuit realization for OTA-C current-mode comb filter is proposed to remove the undesirable multiple frequency signals. The proposed filter uses only OTAs and capacitors, hence suitable for monolithic integrated circuit implementation. The proposed OTA-C comb filter is simulated in PSPICE using a behavioral macro-model of the OTA as well with a practical CMOS OTA circuit. The workability of the comb filter is verified for hum signal frequencies of 60, 180 and 300 Hz that are found in bio-medical signals. The results obtained are in good agreement with theory.

Keywords: Operational Transconductance Amplifier (OTA); Continuous-time (CT) or analog filter; Voltage-mode and current-mode filter; Single-Output OTA (SO-OTA); Dual-Output OTA (DO-OTA); CMOS OTA; Harmonic interference; Comb filter