Yazar "Herencsar, Norbert" seçeneğine göre listele

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    An Additional Approach to Model Current Followers and Amplifiers with Electronically Controllable Parameters from Commercially Available ICs
    (Sciendo, 2012) Sotner, Roman; Kartçı, Aslıhan; Jerabek, Jan; Herencsar, Norbert; Dostal, Tomas; Vrba, Kamil
    Several behavioral models of current active elements for experimental purposes are introduced in this paper. These models are based on commercially available devices. They are suitable for experimental tests of current- and mixed-mode filters, oscillators, and other circuits (employing current-mode active elements) frequently used in analog signal processing without necessity of on-chip fabrication of proper active element. Several methods of electronic control of intrinsic resistance in the proposed behavioral models are discussed. All predictions and theoretical assumptions are supported by simulations and experiments. This contribution helps to find a cheaper and more effective way to preliminary laboratory tests without expensive on-chip fabrication of special active elements.
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    Design of Novel Precise Quadrature Oscillators Employing ECCIIs with Electronic Control
    (Univ Suceava, Fac Electrical Eng, 2013) Sotner, Roman; Lahiri, Abhirup; Kartçı, Aslıhan; Herencsar, Norbert; Jerabek, Jan; Vrba, Kamil
    In this paper, an interesting design of precise quadrature oscillator employing electronically controllable current conveyors of the second generation (ECCII) is presented. The main purpose of this paper is to show advantages and features of direct electronic control of application by an adjustable current gain where help of signal flow graph approach was used to clearer and visual understanding of the design. The discussed circuit and its presented modification have several favorable features such as grounded capacitors, independent electronic adjusting of oscillation frequency and condition of oscillation by the current gain and easy automatic gain control circuit (AGC) implementation (non-ideal effects of tuning process on output amplitudes are suppressed). Oscillator was designed for frequency band of units of MHz and tested with two types of inertial AGCs. Theoretical presumptions were confirmed by laboratory experiments.
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    New Double Current Controlled Cfa (Dcc-Cfa) Based Voltage-Mode Oscillator with Independent Electronic Control of Oscillation Condition and Frequency
    (Slovak Univ Technology, 2013) Sotner, Roman; Herencsar, Norbert; Jerabek, Jan; Dvorak, Radek; Kartçı, Aslıhan; Dostal, Tomas; Vrba, Kamil
    In this paper, a new electronically tunable quadrature oscillator (ETQO) based on two modified versions of current feedback amplifiers (CFAs), the so called double current controlled CFA (DCC-CFAs) is presented. The frequency of oscillation (FO) of the proposed voltage-mode (VM) ETQO is electronically adjustable by current gain or by varying the intrinsic resistance of the X terminal of the active element used. The condition of oscillation (CO) is adjustable by current gain independently with respect to frequency of oscillation. Simultaneous control of current gain and intrinsic resistance allows linear control of FO and provides extension of frequency tuning range. In the proposed circuit all the capacitors are grounded. The use of only grounded capacitors makes the proposed circuit ideal for integrated circuit implementation. The presented active element realized by using BiCMOS technology and the behavior of proposed circuit are discussed in details. The theoretical results are verified by SPICE simulations based on CMOS ON-Semi C5 0.5 mu m and bipolar ultra high frequency transistor arrays Intersil HFA 3096 process parameters.