A Current-Mode Universal Frequency Filter Using Transconductace Amplifiers and Transimpedance Amplifier

摘要

A new filtering structure of the 2nd-order universal frequency filter is presented. The proposed filter operates in current-mode and is designed using signal-flow graphs (SFG) method. Operational transconductance amplifiers (OTAs), current follower (CF) and transimpedance amplifier (TIA) are used in the proposal. The filter possesses of ability to adjust the pole frequency and quality factor of the filter independently of each other. All output responses are taken directly from high-impedance outputs of used active elements. The proposal requires only two external passive elements, namely two capacitors which are both grounded. The proper function of the proposed filter is verified by PSpice simulations and also by experimental measurements. Demonstrations of possibility to independently tune the pole frequency and quality factor of the proposed filter are illustrated in the paper. Subsequently, comparison of results obtained from simulations and experimental measurements is also included.