Triple-input Single-output Voltage-mode Multifunction Filter Using Only Two Current Conveyors

Abstract

Abstract —A new voltage-mode triple-input single-output multifunction filter using only two current conveyors is presented. The proposed filter which possesses three inputs and single-output can generate all biquadratic filtering functions at the output terminal by selecting different input signal combinations. The validity of the proposed filter is verified through PSPICE simulations. Keywords — Active Filters, Voltage mode, Current conveyor I. I NTRODUCTION oltage mode circuits using conventional operational amplifiers have the disadvantage of severely reduced bandwidth at higher gains because of the op-amp’s fixed gain-bandwidth product. These disadvantages can be eliminated by using current conveyors [1-3]. Recently, many single and multi-output voltage mode universal biquadratic filters using current conveyors have been reported in the literature [4-10]. Some of these filters employ two positive-type second-generation current conveyors (CCII+) and one voltage follower [5, 9]. Some other filters employ one positive-type second-generation current conveyor, one negative-type second-generation current conveyor (CCII-), two capacitors and three resistors [6, 8]. Liu et al. reported a voltage-mode filter which employs one CCII+, one CCII-, two capacitors and three resistors [8]. Chang proposed a voltage-mode filter which employs three CCII+s, two capacitors and three resistors [4]. Later, Chang and Tu presented a voltage-mode filter which uses two CCII+, two capacitors and three resistors with orthogonal control over the natural frequency and the quality factor. However, this filter has four inputs and its transfer function is very complex [5]. Horng proposed a voltage-mode filter which employs three CCII+, two capacitors and two resistors [10]. In this paper, a new voltage-mode triple-input single-output multifunction filter using only two current conveyors is presented. The circuit uses one positive-type, one negative-