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A novel current-mode (CM) single-input and three-output (SITO) universal filter using two second generation current controlled conveyors (CCCIIs), one current follower (CF) and two capacitors is presented. The circuit is fully programmable and implements all the five generic filtering functions. The lowpass (LP), bandpass (BP), and highpass (HP) functions can be realized simultaneously while Notch (BS) and allpass (AP) responses can be implemented simply by connecting the appropriate node currents without requiring additional elements. The availability of currents at high impedances, facilitate cascadibility feature. The filter performance factors ω 0 and ω 0 /Q are electronically tunable through separate bias currents of the CCCIIs. SPICE simulation results are included to confirm the workability of the proposed circuit.

This paper presents a novel circuit configuration for realizing voltage-mode three input and one-output type universal filter based on and employing a single current feedback amplifier (CFA), two operational transconductance amplifiers (OTAs) and as many capacitors. The employments of OTAs provide electronic tuning capability to pertinent filter characteristics, which is highly desirable in 1C design. The circuit offers the following features: realization of all standard filtering functions from the same configuration, no use of resistors, no imposition of component matching conditions, orthogonal control of natural frequency and bandwidth, low active and passive sensitivities, minimum active and passive components and cascadibility. PSPICE simulation results are included.Index Terms Current feedback amplifier, operational transconductance amplifier, active filters Frequenz 58 (2004) 7-8

A novel filtering topology with a single input and three outputs (SITO) employing a single four-terminal current feedback amplifier (CFA) with an external compensation pin, such as AD844, two operational amplifiers (OAs), and as many resistors is presented. The circuit offers the features of simultaneous realization of lowpass (LP), bandpass (BP), and highpass (HP) filtering functions, free from component matching conditions, cascadability due to high input and low output impedances, orthogonal/independent adjustment of the filtering parameters, and low active and passive sensitivities. PSPICE simulation results are included to confirm the theoretical results.