Electronically tunable versatile voltage-mode universal filter

Department of Electronic Engineering, De-Lin Institute of Technology, Taiwan, ROC
AEU - International Journal of Electronics and Communications (Impact Factor: 0.7). 04/2008; DOI: 10.1016/j.aeue.2007.04.008

ABSTRACT A novel electronically tunable versatile voltage-mode universal biquad filter by using two single-output-operational transconductance amplifiers (OTAs), one differential difference current conveyor (DDCC) and two capacitors is proposed. The proposed circuit, which can be used as either a four-input single-output universal filter or a single-input three-output multifunction filter with the same topology. Besides, the new circuit offers the following advantageous features: realization of all the non-inverting and inverting biquadratic filter signals from the same configuration, no need to employ inverting-type input signals, no need to component-matching conditions and low passive sensitivity performance.

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    ABSTRACT: This paper presents a electronically tunable voltagemode universal biquadratic filter with three inputs and one output using three single-ended operational transconductance amplifiers and two capacitors. The proposed filter provides low-pass, band-pass, high-pass, band-stop and all-pass filters by appropriately connecting the input terminals. No component-matching condition is required for realizing these filtering functions. The use of minimum elements makes the filter possible for low power consumption applications. The natural frequency and the quality factor can be set orthogonally by adjusting the circuit components. Also the natural frequency can be electronically tuned via the bias currents of OTAs. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.
    Proceedings of the 2013 4th International Conference on Intelligent Systems, Modelling and Simulation; 01/2013
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    ABSTRACT: This paper presents a new voltage-mode multifunction filter with four inputs and three outputs employing three current controlled differential difference current conveyors (CCDDCCs) and two grounded capacitors. The proposed circuit can provide low-pass, band-pass, high-pass, band-stop and all-pass voltage responses by appropriately connecting the input and output terminals, at a high impedance input terminal which enable easy cascadability. The circuit parameters ωo and Q can be set orthogonally by adjusting the circuit components. PSPICE simulation results are also performed to confirm the theoretical analysis. Keywords—Multifunction filter, Voltage-mode circuit; Current controlled differential difference current conveyors (CCDDCCs)
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    ABSTRACT: In this paper, a circuit employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs) as active element is proposed which can function both as biquad filter and oscillator. It uses two CCCCTAs and two capacitors. As a biquad filter it can realizes all the standard filtering functions (low pass, band pass, high pass, band reject and all pass) in voltage-mode and provides the feature of electronically and orthogonal control of pole frequency and quality factor through biasing current(s) of CCCCTAs. The proposed circuit can also be worked as oscillator without changing the circuit topology. Without any resistors and using capacitors, the proposed circuit is suitable for IC fabrication. The validity of proposed filter is verified through PSPICE simulations.


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