Conference Papers 1998 with Abstracts

1. M. F. Hribsek and D. V. Tosic, "Versatile OTA filter sections with independent pole-frequency and bandwidth control," Proc. 2nd IMACS International Conference on: Circuits, Systems and Computers, IMACS-CSC'98, ISBN 960-8485-06-1, vol. 2, Piraeus, Greece, October 26-29, 1998, pp. 956-958.
   Abstract A simple design procedure of a versatile active filter using operational transconductance amplifier (OTA) is presented. The filter can simultaneously perform high, low and bandpass filtering. The use of OTAs enables the mutually independent control of the pole frequency and bandwidth. The computer simulation shows an excellent agreement with the theory developed.

2. D. V. Tosic, M. D. Lutovac, B. L. Evans, I. M. Markoski, "A tool for symbolic analysis and design of analog active filters," Proc. 5th International Workshop on Symbolic Methods and Applications to Circuit Design, SMACD'98, ISSN 1029-9505, Kaiserslautern, Germany, October 8-9, 1998, pp. 71-74.
   Abstract In this paper we introduce a tool for symbolic analysis and design of analog active filters. It has been developed in Mathematica. The tool can be used to draw circuit schematics, and to formulate and solve analysis and design equations. We present a closed-form solution for a design problem that would otherwise only be possible by numerical optimization or trial-and-error guessing and simulation. Illustrative examples are given to demonstrate filter design with minimization of the sensitivity, and optimization of element values to prescribed values.

3. M. D. Lutovac, D. V. Tosic, I. M. Markoski, "Symbolic computation of elliptic rational functions," Proc. 5th International Workshop on Symbolic Methods and Applications to Circuit Design, SMACD'98, ISSN 1029-9505, Kaiserslautern, Germany, October 8-9, 1998, pp. 177-180.
   Abstract Elliptic rational functions have been traditionally derived from the Jacobi elliptic functions that are computationaly intensive. In this paper we construct the elliptic rational function, in the closed form, bypassing mathematical theory of special functions. We build the knowledge of the elliptic rational function using simple algebraic manipulations, only. A nesting property of elliptic rational functions is presented.

4. D. V. Tosic, M. D. Lutovac, "Symbolic computation of impulse, step and sine response of linear time-invariant systems," Proc. VI international SAUM conference on Systems, Automatic Control and Measurements, Nis, Serbia, Yugoslavia, 1998, pp. 213-216.
   Abstract The paper presents symbolic computation of impulse, step and sine responses of linear time-invariant systems. The responses are derived as closed-form expressions in terms of the system parameters kept as symbols. An original algorithm coded in Mathematica, to find these responses, is given. Its output is very close to the traditional form, and offers clear insight into the result. The performance of the new code is compared to the similar existing Mathematica function, and the advantages of the proposed solution are discussed.

5. M. F. Hribsek, D. V. Tosic, "Design of a simple electronically controlled octave equalizer," Proc. VI international SAUM conference on Systems, Automatic Control and Measurements, Nis, Serbia, Yugoslavia, 1998, pp. 176-178.
   Abstract An octave constant Q-factor graphic equalizer using a new class of active bandpass filters is presented. It covers all eleven standard octaves in frequency range from 16 Hz to 20 kHz. The level in each octave can be changed within +/- 20 dB with respect to the reference level which corresponds to the zero-dB gain of the equalizer. The advantages of the proposed bandpass biquads are the use of only one operational amplifier per octave, a very small resistor-value spread ratio, and equal values of the resistors in all octaves. The computer simulation has been used to verify the design of the novel circuit. The new design has been compared to the existing solutions reported in open literature. The comparison shows excellent agreement in frequency response with the published results. The effects of the finite gain and bandwidth of the real operational amplifier have been investigated. The proposed new equalizer showed to be robust against imperfections of the operational amplifiers.

6. N. Damera-Venkata, B. L. Evans, M. D. Lutovac, and D. V. Tosic, "Joint Optimization of Multiple Behavioral and Implementation Properties of Analog Filter Designs," Proc. IEEE Int. Sym. on Circuits and Systems ISCAS'98, May 31-Jun. 3, 1998, pp. 286-289.
   Abstract This paper presents an extensible framework for optimizing analog filter designs for multiple behavioral and implementation properties. We demonstrate the framework using the behavioral properties of magnitude response, phase response, and peak overshoot, and the implementation property of quality factors. We represent the analog filter in terms of its poles and zeroes. We match the constrained non-linear optimization problem to a sequential quadratic programming (SQP) problem, and develop symbolic mathematical software to translate the SQP formulation into working MATLAB programs to optimize analog filter designs. The automated approach avoids errors in algebraic calculations and errors in transcribing the mathematical equations in software. The packages are freely distributable.

7. M. D. Lutovac, D. V. Tosic, D. Novakovic, "Programmable low-pass/high-pass SC-filters," Proc. 9th Mediterranean Electrotechnical Conference, MELECON'98, Tel-Aviv, Israel, May 1998, vol. I, pp. 673-677.
   Abstract Application notes released by manufacturers rely on the classical filter design; often, these notes suggest standard modes of operation of the SC integrated chip that are suitable for different filter types and realizations. In this paper we modify a standard mode of operation of a universal SC filter to design very selective and robust filters based on commercially available integrated switched capacitor (SC) universal building blocks. A lowpass or highpass filter is obtained by single control signal.

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8. M. F. Hribsek, D. V. Tosic, "Naponom kontrolisani OTA-C filtar," Proc. XLII conf. ETRAN, Vrnjacka Banja, Serbia, Yugoslavia, 1998, vol. 1, pp. 133-135.
   Abstract Prikazana je realizacija aktivnog filtra sa kondenzatorima i operacionim transkonduktansnim integrisanim pojacavacima (OTA) cije se karakteristike mogu podesavati kontrolnim naponom u sirokom opsegu. Ovakav filter se istovremeno moze koristiti kao propusnik niskih, visokih i opsega ucestanosti. Osobine ovog filtra su uporedjene sa karakteristikama odgovarajuceg filtra realizovanog sa klasicnim operacionim pojacavacem.

9. M. D. Lutovac, D. V. Tosic, "Digital filter design using MATLAB and Mathematica," Proc. VI conf. TELFOR, Belgrade, Serbia, Yugoslavia, 1998, pp. 354-359. (INVITED PAPER)
   Abstract The principal drawback of the classical digital filter design is in returning only one solution, which can be unacceptable for many practical implementations. We propose an advanced approach to the filter design by using a mixture of symbolic and numeric computation and discrete non-linear optimization, in Mathematica and MATLAB. This approach should provide reduced filter complexity for a desired performance, or better performances for the required complexity.

Last updated 1998/11/25 00:07.