# September 2010, Volume 19, Number 3

**V. Sedenka, Z. Raida**
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Critical Comparison of Multi-objective Optimization Methods: Genetic Algorithms versus Swarm Intelligence

The paper deals with efficiency comparison of two global evolutionary optimization methods implemented in MATLAB. Attention is turned to an elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) and a novel multi-objective Particle Swarm Optimization (PSO). The performance of optimizers is compared on three different test functions and on a cavity resonator synthesis. The microwave resonator is modeled using the Finite Element Method (FEM). The hit rate and the quality of the Pareto front distribution are classified.

- LUKES, Z., RAIDA, Z. Multi-objective optimization of wire antennas: genetic algorithms versus particle swarm optimization. Radioengineering, 2005, vol. 14, no. 4, p. 91-97.
- DEB, K. Multi-Objective Optimization using Algorithms. Chichester: John Wiley and Sons, 2001. Evolutionary
- BANDYOPADHYAY, S., SAHA, S., MAULIK, U., DEB, K. A simulated annealing-based multiobjective optimization algorithm: AMOSA. IEEE Transactions on Evolutionary Computation, 2008, vol. 12, no. 3, p. 269-283.
- ZITZLER, E., DEB, K., THIELE, L. Comparison of multiobjective evolutionary algorithms: Empirical results. Evolutionary Computation, 2000, vol. 8, no. 2, p. 173-195.
- GROŞAN, C., DUMITRESCU, D. A comparison of multiobjective evolutionary algorithms. Acta Universitatis Apulensis, 2002, vol. 4.
- HOLLAND, J. H. Outline for a logical theory of adaptive systems. J. Assoc. Comput. Mach. 1962, vol. 3, p. 297–314.
- DEB, K., PRATAP, A., AGARWAL, S., MEYARIVAN, T. A fast and elitist multi-objective genetic algorithm-NSGA-II. KanGAL Report. 2000, no. 2000001. [Online] Available at: http://www.iitk.ac.in/kangal/papers/tech2000001.ps.gz.
- KENNEDY, J., EBERHART, R. C. Particle swarm optimization. IEEE Conference on Neural Networks. Perth (Australia), 1995, p. 1942-1948.
- REYES-SIERRA, M., COELLO COELLO, C. A. Multi-objective particle swarm optimizers: A survey of the state-of-the-art. International Journal of Computational Intelligence Research, 2006, vol. 2, no. 3, p. 287-308. [Online] Available at: http://www.softcomputing.net/ijcir/vol2-issu3-paper5.pdf
- JOHNSON, J. M., RAHMAT-SAMII, Y. Genetic algorithms in engineering electromagnetics. IEEE Antennas and Propagation Magazine, 1997, vol. 39, no. 4, p. 7-21.
- SILVESTER, P. P., FERRARI, R. L. Finite Elements for Electrical Engineers. 3rd ed. Cambridge: Cambridge University Press, 1996.
- CHEN, L. F., ONG, C. K., NEO, C. P., VARADAN, V. V., VARADAN, V. K. Microwave Electronics: Measurement and Materials Characterization. John Wiley and Sons, 2004.
- GEUZAINE, C., REMACLE, J. F. Gmsh Reference Manual. 233 pages. [Online] Cited 2010-01-05. Available at: http://www.geuz.org/gmsh/doc/texinfo/gmsh.pdf.
- ROBINSON, J., RAHMAT-SAMII, Y. Particle swarm optimization in electromagnetics. IEEE Transactions on Antennas and Propagation, 2004, vol. 52, no. 2, p. 397-407.
- JIN, Y., OKABE, T., SENDHOFF, B. Solving three-objective optimization problems using evolutionary dynamic weighted aggregation: Results and analysis. [Online] Available at: http://www.soft-computing.de/moo3D.pdf.

Keywords: Multi-objective optimization, binary genetic algorithm, particle swarm optimization, Pareto front, finite element method.

**S. Rupcic, V. Mandric, S. Rimac-Drlje**
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Fabrication Errors Influence on the Sperical Array Radiation Pattern

The paper studies fabrication errors influence on the radiation pattern of a spherical antennas array. The developed Moment Method (MoM) program analyzes a particular influence of an azimuth and elevation position and local angle errors of antenna elements as well as model dimension errors on the radiation pattern. The spectral domain approach to the analysis of the spherical antenna arrays is applied here. Finally, results obtained from the theoretical investigation are verified by comparison with measured results.

- RUTZ-PHILIPP, E. M. Spherical retrodirective array. IEEE Trans. on Antennas and Propagation, 1964, p. 187-194.
- SENGUPTA, D. L., FERRIS, J. E., LARSON, R., SMITH, T. M. Azimuth and elevation direction finder study. Radiation Lab., University of Michigan, Ann.Arbor, Rept. 7577-1-Q, AD 479635L, 1965., Rept. 7577-2-Q, 1966.
- SENGUPTA, D. L., FERRIS, J. E., SMITH, T. M. Experimental study of a spherical array of circularly polarized elements. Proceedings of the IEEE, 1968, p. 2048-2051.
- SENGUPTA, D. L., SMITH, T. M., LARSON, R. W. Radiation characteristics of spherical array of circularly polarized elements. IEEE Trans. on Antennas and Propagation, 1968, vol. 16, p. 2-7.
- CHAN, A. K., SIGELMANN, R. A. Experimental investigation on spherical arrays. IEEE Trans. on Antennas and Propagation, 1969, p. 348-349.
- HESSEL, A., LIU, Y.-L., SHMOYS, J. Mutual admittance between circular apertures on a large conducting sphere. Radio Science, 1979, vol. 14, no. 1, p.35-41.
- KHAMAS, S. K. Electromagnetic radiation by antennas of arbitrary shape in a layered spherical media. IEEE Trans. on Antennas and Propagation, 2009, vol. 57, no. 12, p. 3827-3833.
- STUART, H. R. Eigenmode analysis of small multielement spherical antennas. IEEE Trans. on Antennas and Propagation, 2008, vol. 56, no. 9, p. 2841-2851.
- FRANEK, O., PEDERSEN, G. F., ANDERSEN, J. B. Numerical modeling of a spherical array of monopoles using FDTD method. IEEE Trans. on Antennas and Propagation, 2006, vol. 54, no. 7, p. 1952-1963.
- GOOSSENS, R., BOGAERT, I., ROGIER, H. Phase-mode processing for spherical antenna arrays with a finite number of antenna elements and including mutual coupling. IEEE Trans. on Antennas and Propagation, 2009, vol. 57, no. 12, p. 3783-3790.
- KORETZ, A., RAFAELY, B. Dolph–Chebyshev beampattern design for spherical arrays. IEEE Transactions on Signal Processing, 2009, vol. 57, no. 6, p. 2417 – 2420.
- YAN, S.-H., CHU, T.-H. A beam-steering antenna array using injection locked coupled oscillators with self-tuning of oscillator free-running frequencies. IEEE Trans. on Antennas and Propagation, 2008, vol. 56, no. 9, p. 2920-2928.
- PETKO, J. S., WERNER, D. H. Positional tolerance analysis and error correction of micro-UAV swarm based antenna arrays. In Antennas and Propagation Society International Symposium, 2009. APSURSI '09. IEEE, 2009, p. 1-4.
- KILDAL, P.-S., SANFORD, J. Analysis of conformal antennas by using spectral domain techniques for curved structures. In Proceedings of COST 245 - ESA workshop on active antennas, Noordwijk, 1996, p. 17-26.
- SIPUS, Z., KILDAL, P.-S., LEIJON, R., JOHANSSON, M. An algorithm for calculating Green’s functions for planar, circular cylindrical and spherical multilayer substrates. Applied Computational Electromagnetics Society Journal, 1998, vol. 13, p. 243-254.
- LEIJON, R. Radiation from mobile phone antennas close to the human body. Technical Report No.270L, Department of Microwave Technology, Chalmers University of Technology, Gothenburg, 1997.
- TAM, W. Y., LUK, K. M. Resonances in spherical-circular microstrip structures. IEEE Trans. on Microwave Theory Tech., 1991, vol. MTT-39, p. 700-704.
- SIPUS, Z., RUPCIC, S., LANNE, M., JOSEFSSON, L. Analysis of circular and spherical array of waveguide elements covered with radome. In Proceedings of IEEE International Symposium on Antennas and Propagation. Boston (USA), 2001, p. 350-353.
- RUPCIC, S. Circular waveguide antenna arrays on spherical structures. PhD dissertation, University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, 2009.
- RUPCIC, S., MANDRIC, V. Model errors of a spherical aperture antennas array. In SIP 2008. Osijek (Croatia), 2008, p. 21 - 26.

Keywords: Radiation pattern, antenna array, aperture antenna, spherical array, fabrication errors, experimental model errors

**A. E. Yilmaz**
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Fine-Tuning on the Effective Patch Radius Expression of the Circular Microstrip Patch Antennas

In this study, the effective patch radius expression for the circular microstrip antennas is improved by means of several manipulations. Departing from previously proposed equations in the literature, one of the most accurate equations is picked up, and this equation is fine-tuned by means of Particle Swarm Optimization technique. Throughout the study, impacts of other parameters (such as the definition of the fitness/objective function, the degree-of-freedom in the proposed effective patch radius expression, the number of measured resonant frequency values) are observed in a controlled manner. Finally, about 3% additional improvement is achieved over a very accurate formula, which was proposed earlier.

- HOWELL, J. Q. Microstrip antennas. IEEE Transactions on Antennas and Propagation, 1975, vol. AP-23, p. 90 – 93.
- DERNERYD, A. G. Microstrip disc antenna covers multiple frequencies. Microwave Journal, 1978, vol. 21, no. 5, p. 77 to 79.
- CARVER, K. R. Practical analytical techniques for the microstrip antenna. In Proceedings of Workshop on Printed Circuit Antenna Technology. Las Cruces (NM, USA), 1979, p. 7.1 – 7.20.
- LIU, Q., CHEW, W. C. Curve-fitting formulas for fast determination of accurate resonant frequency of circular microstrip patches. IEE Proc. H, 1988, vol. 135, no. 5, p. 289 to 292.
- ABBOUD, F., DAMIANO, J. P., PAPIERNIK, A. New determination of resonant frequency of circular microstrip patches. Electronics Letters, 1988, vol. 24, no. 17, p. 1104 to 1106.
- ROY, J. S., JECKO, B. A formula for the resonance frequencies of circular microstrip patch antennas satisfying CAD requirements. International Journal of Microwave & Millimeter-Wave Computer Aided Engineering, 1993, vol. 3, no. 1, p. 67 – 70.
- GUNEY, K. Resonant frequency of electrically thick circular microstrip antennas. International Journal of Electronics, 1994, vol. 77, no. 3, p. 377 – 386.
- LEE, K. F., FAN, Z. CAD formulas for resonant frequencies of TM11 mode of circular patch antenna with or without substrate. Microwave and Optical Technology Letters, 1994, vol. 7, p. 570 to 573.
- KUMPRASERT, N., KIRANON, W. Simple and accurate formula for the resonant frequency of the circular microstrip disk antenna. IEEE Transactions on Antennas and Propagation, 1995, vol. 43, p. 1331 – 1333.
- AKDAGLI, A., GUNEY, K. Effective patch radius expression obtained using a genetic algorithm for the resonant frequency of electrically thin and thick circular microstrip antennas. IEE Proceedings – Microwaves, Antennas and Propagation, 2000, vol. 147, no. 2, p. 156 – 159.
- ITOH, T., MITTRA, R. Analysis of a microstrip disk resonator. Archiv fur Elektronik und Ubertragungstechnik, 1973, vol. 27, no. 11, p. 456 – 458.
- DAHELE, J. S., LEE, K. F. Effect of substrate thickness on the performance of a circular-disk microstrip antenna. IEEE Transactions on Antennas and Propagation, 1983, vol. AP-31, no. 2, p. 358 – 364.
- DAHELE, J. S., LEE, K. F. Theory and experiment on microstrip antennas with airgaps. IEE Proceedings H - Microwaves Optics and Antennas, 1985, vol. 132, no. 7, p. 455 to 460.
- ANTOSKIEWICZ, K., SHAFAI, L. Impedance characteristics of circular microstrip patches. IEEE Transactions on Antennas and Propagation, 1990, vol. AP-38, no. 6, p. 942 – 946.
- LONG, S. A., SHEN, L. C., WALTON, M. D., ALLERDING, M. R. Impedance of a circular disk printed-circuit antenna. Electronics Letters, 1978, vol. 14, no. 21, p. 684 – 686.
- YANO, S., ISHIMARU, A. A theoretical study of the input impedance of a circular microstrip disk antenna. IEEE Transactions on Antennas and Propagation, 1981, vol. AP-29, p. 77 – 83.
- DAVIDOVITZ, M., LO, Y. T. Input impedance of a probe-fed circular microstrip antenna with thick substrate. IEEE Transactions on Antennas and Propagation, 1986, vol. AP-34, p. 905 – 911.
- LOSADA, V., BOIX, R. R., HORNO, M. Resonant modes of circular microstrip patches in multilayered substrates. IEEE Transactions on Microwave Theory and Techniques, 1999, vol. MTT-47, p. 488 – 497.
- HOLLAND, J. H. Adaptation of Natural and Artiﬁcial System. Ann Arbor: University of Michigan Press, 1976.
- KENNEDY, J., EBERHART, R. C. Particle swarm optimization. In Proceedings of the IEEE Conference on Neural Networks. Perth (Australia), 1995, p. 1942 – 1948.
- SHI, Y., EBERHART, R. C. A modified particle swarm optimizer. In Proceedings of the IEEE International Conference on Evolutionary Computation. Anchorage (AK, USA), 1998, p. 69 – 73.
- CLERC, M., KENNEDY, J. The particle swarm: explosion, stability and convergence in a multi-dimensional complex space. IEEE Transactions on Evolutionary Computation, 2002, vol. 6, no. 1, p. 58 – 73.
- XU, S., RAHMAT-SAMII, Y. Boundary conditions in particle swarm optimization revisited. IEEE Transactions on Antennas and Propagation, 2007, vol. AP-55, no. 3, p. 760 – 765.

Keywords: Circular microstrip patch antenna, Closed-form expression, Effective patch radius, Particle swarm optimization, Resonant frequency.

**P. Vagner, M. Kasal**
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A Novel Bandpass Filter Using a Combination of Open-Loop Defected Ground Structure and Half-Wavelength Microstrip Resonators

This paper deals with a defected ground structure (DGS) open-loop resonator analysis and bandpass filter design, using coupled DGS and microstrip resonators. The combination of DGS and microstrip resonators allows using top and bottom sides of the microwave substrate, therefore the resonators can partially overlap and a desired coupling coefficient can be easily achieved. The open-loop DGS resonator properties are investigated, as well as coupling types between the resonators. Finally, two bandpass filters are designed and simulated. The sixth order filter is fabricated and the results are compared with measurement. The introduced structure represents an alternative to a conventional parallel-coupled half wavelength microstrip resonator bandpass filter.

- ABDEL-RAHMAN, A., ALI, A. R., AMARI, S., OMAR, A. S. Compact bandpass filters using defected ground structure (DGS) coupled resonators. In Microwave Symposium Digest, 2005 IEEE MTT-S International, 12-17 June 2005.
- ALI, A. R., ABDEL-RAHMAN, A., AMARI, S., OMAR, A. S. Direct and cross-coupled resonator filters using defected ground structure (DGS) resonators. In Proceedings of the European Microwave Conference 2005, 4-6 October 2005.
- VAGNER, P. Microstrip filters using defected ground structure. Dissertation Thesis, Brno University of Technology, Faculty of Electrical Engineering and Communication, Brno 2008. 108 pages (in Czech).
- HONG, J. S., LANCASTER, M. J. Microstrip Filters for RF/Microwave Applications. John Wiley & Sons, Inc. 2001. 460 pages. ISBN 0-471-38877-7.

Keywords: Defected ground structure (DGS), bandpass filter, DGS resonator, slot resonator, open-loop resonator, half-wavelength microstrip resonator, Chebyshev prototype filter

**P. Kejik, S. Hanus**
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Admission Control Techniques for UMTS System

Universal mobile telecommunications system (UMTS) is one of the 3rd generation (3G) cell phone technologies. The capacity of UMTS is interference limited. Radio resources management (RRM) functions are therefore used. They are responsible for supplying optimum coverage, ensuring efficient use of physical resources, and providing the maximum planned capacity. This paper deals with admission control techniques for UMTS. An own UMTS simulation program and several versions of proposed admission control algorithms are presented in this paper. These algorithms are based on fuzzy logic and genetic algorithms. The performance of algorithms is verified via simulations.

- ROMERO, J., SALLENT, O., AGUSTI, R., DIAZ-GUERRA, M. Radio Resources Management Strategies in UMTS. Wiley & Sons, 2005, 345 p. ISBN 978-0-470-02277-1.
- ELAYOUBI, S., CHAHED, T. Admission control in the downlink of WCDMA/UMTS. Wireless systems and mobility in next generation internet. Lecture Notes in Computer Science, Springer, Heidelberg, vol. 3427/2005, p. 136-151. ISBN 978-3-540-25329-7
- LEVINE, D., AKYILDIZ, I., NAGHSHINEH, M. A resource estimation and call admission algorithm for wireless multimedia networks using the shadow cluster concept. IEEE/ACM Transactions on Networking, 1997, vol. 5, no. 1.
- CAPONE, A., REDANA, S. I3E: A novel call admission control scheme for W-CDMA systems. Wireless Personal Communication. Springer Netherlands, Oct. 2006, vol. 39, no. 1, p. 81-97. ISSN 1572-834X.
- LIU, D., ZHANG, Y., HU, S. Call admission policies based on calculated power control setpoints in SIR-based power-controlled DS-CDMA cellular networks. Wireless Networks, Springer Netherlands, 2004, vol. 10, no. 4, p. 473-483. ISSN 1572-8196.
- MALARKKAN, S., RAVICHANDRAN, V. Performance analysis of call admission control in WCDMA systems with adaptive multi class traffic based on fuzzy logic. IJCSNS International Journal of Computer Science and Network Security, Nov. 2006, vol. 6, no. 11.
- SHEN, S., CHANG, C., HUANG, C., BI, Q. Intelligent call admission control for wideband CDMA cellular systems. IEEE Transactions on Wireless Communications, Sept. 2004, vol. 3, no. 5.
- YENER, A., ROSE, C. Genetic algorithms applied to cellular call admission problem: Local policies. IEEE Transactions on Vehicular Technology, Feb. 1997, vol. 46, p. 72-79.
- KARABUDAK, D., HUNG, C., BING, B. A call admission control scheme using genetic algorithms. In Proceedings of the 2004 ACM symposium on Applied Computing, 2004. ISBN 1-58113-812-1.
- BAIK, S., BALA, J., HADJARIAN, A., PACHOWICZ, P. Genetic evolution approach for target movement prediction. In Lecture Notes in Computer Science. Springer, Heidelberg, vol. 3037/2004, p. 678-681. ISBN 978-3-540-22115-9.
- AYYAPPAN, K., KUMAR, R. Service utilization based call admission control (CAC) scheme for WCDMA network. International Journal of Research and Reviews in Computer Science (IJRRCS), June 2010, vol. 1, no. 2, p. 66-70. ISSN 2079- 2557.
- CHANG, CH., KUO, L., CHEN, Y., SCHEN, S. Neural fuzzy call admission and rate controller for WCDMA cellular systems providing multirate services. In Proceedings of the 2006 International Conference on Wireless Communications and Mobile Computing. Canada, p. 383-388. ISBN 1-59593-306-9.
- LO, J., BRITO, A., CORREIA, L., CORREIA, A. Simulation of call admission control, load control, handover and power control algorithms for enhanced UMTS. SEACORN Project. [Online] Cited 2009-11-19. Available at http://seacorn.cs.ucy.ac.cy/eumtssim/.

Keywords: UMTS, CDMA, admission control, fuzzy logic, genetic algorithms

**I. Develi, K. Kockaya**
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BER Performance Simulation of Generalized MC DS-CDMA System with Time-Limited Blackman Chip Waveform

Multiple access interference encountered in multicarrier direct sequence-code division multiple access (MC DS-CDMA) is the most important difficulty that depends mainly on the correlation properties of the spreading sequences as well as the shape of the chip waveforms employed. In this paper, bit error rate (BER) performance of the generalized MC DS-CDMA system that employs time-limited Blackman chip waveform is presented for Nakagami-m fading channels. Simulation results show that the use of Blackman chip waveform can improve the BER performance of the generalized MC DS-CDMA system, as compared to the performances achieved by using timelimited chip waveforms in the literature.

- ANJARIA, R., WYRWAS, R. The effect of chip waveform on the performance of CDMA systems in multipath, fading, noisy channels. In Proceedings of IEEE 42nd Vehicular Technology Conference. USA, 1992, p. 672 - 675.
- DALLAS, P. I., PAVLIDOU, F. N. Innovative chip waveforms in microcellular DS/CDMA packet mobile radio. IEEE Transactions on Communications, 1996, vol. 44, no. 11, p. 1413 - 1416.
- GERANIOTIS, E. A., PURSLEY, M. B. Performance of coherent direct-sequence spread-spectrum communications over specular multipath-fading channels. IEEE Transactions on Communica- tions, 1985, vol. 33, no. 6, p. 502 - 508.
- GLANCE, B., GREENSTEIN, L. J. Frequency-selective fading effects in digital mobile radio with diversity combining. IEEE Transactions on Communications, 1983, vol. 31, no. 9, p. 1085 to 1094.
- HARA, S., PRASAD, R. Overview of multicarrier CDMA. IEEE Communications Magazine, 1997, vol. 35, no. 12, p. 126 - 133.
- HARA, S., PRASAD, R. Design and performance of multicarrier CDMA system in frequency-selective Rayleigh fading channels. IEEE Transactions on Vehicular Technology, 1999, vol. 48, no. 5, p. 1584 - 1595.
- KIM, Y. W., KIM, Y. V., KIM J. H. et al. A comparison of system performance using two different chip pulses in multiple-chip-rate DS/CDMA systems. IEEE Transactions on Communications, 2001, vol. 49, no. 11, p. 1988 - 1996.
- KIM, D. K., HWANG, S. H. Capacity analysis of an uplink synchronized multicarrier DS-CDMA system. IEEE Communica- tions Letters, 2002, vol. 6, no. 3, p. 99 - 101.
- KOCKAYA, K. Investigation of the variation of optimum subcarrier spacing for generalized MC DS-CDMA system with different chip waveforms. M.Sc. Thesis, Department of Electrical and Electronics Engineering, Graduate School of Natural and Applied Sciences, Erciyes University, 2008.
- KOCKAYA, K., DEVELI, I. BER performance of generalized multicarrier DS-CDMA system with Blackman chip waveforms over Nakagami-m fading channels (in Turkish). In Proceedings of IEEE 16th Signal Processing, Communication and Applications Conference. Didim (Turkey), 2008, CD-ROM.
- KOK, B. K., DO, M. A. Effects of spreading chip waveform pulse- shaping on the performance of DS-CDMA indoor radio personal communication systems in a frequency-selective Rician fading channel. In Proceedings of IEEE International Symposium on Consumer Electronics. Singapore, 1997, p. 198 - 201.
- LANDOLSI, M. A., STARK, W. E. DS-CDMA chip waveform design for minimal interference under bandwidth, phase, and envelope constraints. IEEE Transactions on Communications, 1999, vol. 47, no. 11, p. 1737 - 1746.
- LEHNERT, J. S. Chip waveform selection in offset-quaternary direct-sequence spread-spectrum multiple access communications. M.Sc. Thesis, Univ. Illinois, Urbana, 1981.
- MISSER, H. S., WIJFFELS, C. A. F., PRASAD, R. Throughput analysis of CDMA with DPSK modulation and diversity in indoor Rician fading radio channels. Electronics Letters, 1991, vol. 27, no. 7, p. 601 - 603.
- NAKAGAMI, M. The m-Distributiona General Formula of Intensity Distribution of Rapid Fading, Statistical Methods of Radio Wave Propagation. New York: Pergamon, 1960.
- NGUYEN, H. H., SHWEDYK, E. On error probabilities of DS- CDMA systems with arbitrary chip waveforms. IEEE Communications Letters, 2001, vol. 5, no. 3, p. 78 - 80.
- NGUYEN, H. H. Performance of multicarrier DS-CDMA systems with time-limited chip waveforms. Canadian Journal on Electrical and Computer Engineering, 2004, vol. 29, no. 1-2, p. 23 - 29.
- OCHSNER, H. Direct-sequence spread-spectrum receiver for communication on frequency-selective fading channels. IEEE Journal on Selected Areas in Communications, 1987, vol. 5, no. 2, p. 188 - 193.
- PURSLEY, M. B. Performance evaluation for phase-coded spread- spectrum multiple-access communication-Part I: System analysis. IEEE Transactions on Communications, 1977, vol. 25, no. 8, p. 795 - 799.
- PURSLEY, M. B., ROEFS, H. F. A. Numerical evaluation of correlation parameters for optimal phases of binary shift-register sequences. IEEE Transactions on Communications, 1979, vol. 27, no. 10, p. 1597 - 1604.
- VANDENDORPE, L. Multitone spread spectrum multiple access communications system in a multipath Rician channel. IEEE Transactions on Vehicular Technology, 1995, vol. 44, no. 2, p. 327 to 337.
- YANG, L. L., HANZO, L. Performance of generalized multicarrier DS-CDMA over Nakagami-m fading channels. IEEE Transactions on Communications, 2002, vol. 50, no. 6, p. 956 - 966.
- YANG, L. L., HANZO, L. Generalized multicarrier DS-CDMA using various chip waveforms. In Proceedings of IEEE Wireless Communications and Networking Conference. USA, 2003, p. 790 to 794.
- YANG, L. L., HANZO, L. Multicarrier DS-CDMA: a multiple access scheme for ubiquitous broadband wireless communications. IEEE Communications Magazine, 2003, vol. 41, no. 10, p. 116 to 124.
- YANG, L. L., HANZO, L. Performance of generalized multicarrier DS-CDMA using various chip waveforms. IEEE Transactions on Communications, 2003, vol. 51, no. 5, p. 748 - 752.

Keywords: BER performance simulation, Generalized MC DS-CDMA system, Blackman chip waveform

**L. Krulikovska, J. Filanova, J. Pavlovic**
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Evolution Strategies in the Multipoint Connections Routing

Routing of multipoint connections plays an important role in final cost and quality of a found connection. New algorithms with better results are still searched. In this paper, a possibility of using the evolution strategies (ES) for routing is presented. Quality of found connection is evaluated from the view of final cost and time spent on a searching procedure.

First, parametrical analysis of results of the ES are discussed and compared with the Prim’s algorithm, which was chosen as a representative of the deterministic routing algorithms.

Second, ways for improving the ES are suggested and implemented. The obtained results are reviewed. The main improvements are specified and discussed in conclusion.

- Routing Algorithms and Switching Techniques (lecture). [Online] Available at: http://pages.cs.wisc.edu/~tvrdik/7/html/Section7.html
- SHUCHI, C. Advanced Algorithms (lecture). 4 pages. [Online] Available at: http://pages.cs.wisc.edu/~shuchi/courses/787- F07/scribe-notes/lecture01.pdf
- Graph Algorithms II (lecture). 6 pages. [Online] Available at: http://www.cs.cmu.edu/~avrim/451f09/lectures/lect1008.pdf
- KVASNICKA, V., POSPICHAL, J., TINO, P. Evolutionary Algorithms (in Slovak). 1st ed. Bratislava: STU, 2000. 223 p. ISDN 80 – 246 – 2000.
- KACUR, J., KOROSI, J. An accuracy optimization of a dialog ASR system utilizing evolutional strategies. In Proceedings of the 5th International Symposium on Image and Signal Processing and Analysis. Istanbul (Turkey), 2007, p. 180-184. ISSN 1845-5921, ISBN 978-953-184-116-0.
- POLEC, J., KARLUBIKOVA, T., VARGIC, R. Probabilistic Models in Telecommunications. Bratislava: STU Publishing House, 2007.
- FIDLER, P., POCTAVEK, J., KOTULIAKOVA, K., POLEC, J. New adaptive ARQ/HARQ scheme using RS coding and ITS throughput analysis. In EUROCON 2009: International IEEE Conference devoted to the 150th Anniversary of Alexander S. Popov. Saint Petersburg (Russia), 2009. Piscataway: IEEE, 2009, p. 1658-1663. ISBN 978-1-4244-3861-7.
- KAPSALIS, A., RAYWARD-SMITH, V. J., SMITH, G. D. Solving the graphical Steiner tree problem using genetic algorithms. Journal of the Operational Research Society, 1993, vol.44, no.4, p. 397 – 406.
- PROCHASKA, J., VARGIC, R. Using digital filtration for Hurst parameter estimation, Radioengineering, 2009, vol. 18, no.2, p. 238-241.

Keywords: Evolution strategies (ES), routing of multipoint connections, optimization

**J. B. Seventline, D. Elizabath Rani, K. Raja Rajeswari**
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Ternary Chaotic Pulse Compression Sequences

In this paper method available for generating ternary sequences is discussed. These sequences are useful in many applications but specifically in synchronization of block codes and pulse compression in radar. The ternary sequences are derived from chaotic maps. It is feasible to achieve simultaneously superior performances in detection range and range resolution using the proposed ternary sequences. The properties of these sequences like autocorrelation function, Peak Side Lobe Ratio (PSLR), ambiguity diagram and performance under AWGN noise background has been studied. The generation of these sequences is much simpler, and the available number of sequences is virtually infinite and not limited by the length of the sequence.

- LEVANON, N., MOZESON, E. Radar Signals. Hoboken, NJ: John Wiley& Sons, Inc., 2004.
- SKOLNIK, M. I. Introduction to Radar Systems. 2nd Ed. McGraw- Hill Book Company, 1980.
- COOK, C. E., BERNFIELD, M. Radar Signals - An Introduction to Theory and Application. New York: Academic press, 1967.
- ACKROYD, M. H. Amplitude and phase modulated pulse trains for radar. The Radio and Elect. Eng., December 1971, vol. 41, pp. 541-552.
- RAO, B. V., DESHPANDE, A. A. Why the barker sequence bit length does not exceed thirteen. Journal of IETE, Nov-Dec 1998, vol. 34, no. 6, pp. 461-462.
- BOEHMER, A. M. Binary pulse compression codes. IEEE Trans. IT-13, April 1967, no. 2, pp. 156-157.
- LINDER, J. Binary sequences upto length 40 with best possible autocorrelation function. Electronic Letters, Oct 1975, vol. 11, no. 21, pp. 507-508.
- VEERABHADRA RAO, K., UMAPATHY REDDY Biphase sequences with low sidelobe autocorrelation function. IEEE Transactions on Aerospace and Electronic Systems, March 1986, vol. 22, no. 2, pp. 128-133.
- MOHARIR, P. S. Signal design. Journal of IETE, Oct. 1976, vol. 41, pp. 381-398.
- MOHARIR, P. S. Ternary Barker codes. Electronics Letters, Oct. 1974, vol. 10, pp. 460-461.
- MOHARIR, P. S., VARMA, S. K., VENKATARAO, K. Ternary pulse compression sequences. J. Inst. Electron. Telecomm. Engrs., 1985, vol. 31, pp. 1-8.
- MOHARIR, P. S., RAJARAJESWARI, K., VENKATARAO, K. Barker progressions. In Proceedings of Workshop on Signal Processing Communications and Networking. Tata McGraw Hill, New Delhi, 1990, pp. 126-133.
- XIN WU, WEIXIAN LIU, LEI ZHAO, JEFFREY S. FU Chaotic phase code for radar pulse compression. In Proceedings of IEEE National Radar Conference. Atlanta (USA), 2001, pp. 279-283.
- ASHTARI, A., THOMAS, G., KINSNER, W., FLORES, B. C. Sufficient condition for chaotic maps to yield chaotic behavior after frequency modulation. IEEE Transactions on Aerospace and Electronic Systems, July 2008, vol. 44, no. 3, pp. 1240-1248.
- ASHTARI, A., THOMAS, G., FLORES, B. C. Radar signal design using chaotic signals. In Proceedings of International Waveform Design and Diversity Conference. Pisa (Italy), June 2007, p. 353-357.
- HEIDARI-BATENI, G., MCGILLEN, C. D. Chaotic sequences for spread spectrum: An alternative to PN- sequences. IEEE, ICSTWC, 1992, pp. 437-440.
- HILBORN, R. C. Chaos and Nonlinear Dynamics: An Introduction for Scientists and Engineers. Oxford University Press, 1994.

Keywords: Pulse Compression, Autocorrelation, Peak side lobe ratio

**T. Fryza**
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A Complete Video Coding Chain Based on Multi-Dimensional Discrete Cosine Transform

The paper deals with a video compression method based on the multi-dimensional discrete cosine transform. In the text, the encoder and decoder architectures including the deﬁnitions of all mathematical operations like the forward and inverse 3-D DCT, quantization and thresholding are presented. According to the particular number of currently processed pictures, the new quantization tables and entropy code dictionaries are proposed in the paper. The practical properties of the 3-D DCT coding chain compared with the modern video compression methods (such as H.264 and WebM) and the computing complexity are presented as well. It will be proved the best compress properties could be achieved by complex H.264 codec. On the other hand the computing complexity - especially on the encoding side - is lower for the 3-D DCT method.

- ADJEROH, D. A., SAWANT, S. D. Error-resilient transmission for 3D DCT coded video. IEEE Transactions on Broadcasting, 2009, vol. 55, no. 2, p. 178–189.
- CHAN, Y-L., SIU, W-C. Variable temporal-length 3-D Discrete Cosine Transform coding. IEEE Transactions on Image Processing, 1997, vol. 6, no. 5, p. 758–763.
- CHASSAING, R. Digital Signal Processing and Applications with the C6713 and C6416 DSK. 1st ed. New Jersey: Wiley & Sons, Inc., 2005.
- FFmpeg project. [Online] Cited 2010-08-13. Available at: http://ffmpeg.org/.
- FRYZA, T., HANUS, S. Algorithms for fast computing of the 3D DCT transform. Radioengineering, 2003, vol. 12, no. 1, p. 23–26.
- FRYZA, T., HANUS, S. Dissimilarity detection in video sequences using variation in time domain. In Radioelektronika 2004 Conference Proceedings. Bratislava (Slovakia), 2004, p. 162–165.
- GHANBARI, M. Standard Codecs: Image Compression to Advanced Video Coding. 1st ed. London: IEE, 2003.
- GONZALEZ, R. C., WINTZ, P. Digital Image Processing. 2nd ed. Boston: Addison Wesley Publishing Company, 1987.
- GRGIC, S., MRAK, M., GRGIC, M. Picture quality measures in image compression systems. In Conference Proceedings EUROCON 2003. Ljubljana (Slovenia), 2003, p. 233–237.
- HUSKA, J., KULLA, P. Content adaptive true motion estimator for H.264 video compression. Radioengineering, 2007, vol. 16, no. 4, p. 68–75.
- LAKHANI, G. Optimal Huffman coding of DCT blocks. IEEE Transactions on Circuits and Systems for Video Technology, 2004, vol. 14, no. 4, p. 522–527.
- LEE, M. C., CHAN, R. K. W., ADJEROH, D. A. Quantization of 3D DCT coefﬁcients and scan order for video compression. Journal of Visual Communication and Image Representation, 1997, vol. 8, no. 4, p. 405–422.
- LU, W.-W., GOUGH, M. P. A Fast-adaptive Huffman coding algorithm. IEEE Transactions on Communications, 1993, vol. 41, no. 4, p. 535–538.
- QURESHI, S. Embedded Image Processing on the TMS320C6000TM DSP, Examples in Code Composer StudioTM and MATLAB. 1st ed. New York: Springer Science+Business Media, Inc., 2005.
- RAO, K. R., YIP, P. Discrete Cosine Transform. Algorithms, Advantages, Applications. 1st ed. San Diego: Academic Press, Inc., 1990.
- RICHARDSON, I. E. G. Video Codec Design. Developing Image and Video Compression Systems. 1st ed. New Jersey: John Wiley & Sons Ltd., 2002.
- TRETTER, S. A. Communication System Design Using DSP Algorithms: With Laboratory Experiments for the TMS320C6701 and TMS320C6711. 1st ed. New York: Springer, 2003.
- WALLACE, G. K. The JPEG still picture compression standard. IEEE Transactions on Consumer Electronics, 1992, vol. 38, no. 1, p. xviii–xxxiv.
- WATKINSON, J. The MPEG Handbook. MPEG-1, MPEG-2, MPEG-4. 2nd ed. Burlington: Focal Press, 2004.
- WebM project. [Online] Cited 2010-06-23. Available at: http://www.webmproject.org/.
- WESTWATER, R., FURHT, B. Three-dimensional DCT video compression techniques based on adaptive quantizers. In Second IEEE International Conference on Engineering of Complex Computer Systems. Montreal (Canada), 1996, p. 189–198.
- WESTWATER, R., FURHT, B. Real-Time Video Compression. Techniques and Algorithms. 1st ed. Boston: Kluwer Academic Publishers, 1997.

Keywords: Video signal processing, data compression, discrete cosine transform, multidimensional coding, digital signal processors.

**R. Stukavec, T. Kratochvil**
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Simulation and Measurement of the Transmission Distortions of the Digital Television DVB-T/H Part 2: Hierarchical Modulation Performance

The paper deals with the second part of results of the Czech Science Foundation research project that was aimed into the simulation and measurement of the transmission distortions of the digital terrestrial television according to DVB-T/H standards. In this part the hierarchical modulation performance characteristics and its simulation and laboratory measurements are presented. The paper deals with the hierarchical oriented COFDM modulator for the digital terrestrial television transmission and DVB-T/H standards and possible utilization of this technique in real broadcasting scenarios – fixed, portable and mobile digital TV, all in one TV channel. Impact of the hierarchical modulation on Modulation Error Rate from I/Q constellations and Bit Error Rates before and after Viterbi decoding in DVB-T/H signal decoding are evaluated and discussed.

- STUKAVEC, R. KRATOCHVIL, T. Simulation and measurement of the transmission distortions of the digital television DVB-T/H Part 1: Modulator for digital terrestrial television. Radioengineering, 2010, vol. 19, no. 2, pp. 338-346. ISSN: 1210-2512
- REIMERS, U. Digital Video Broadcasting, The Family of International Standards for Digital Television. 2nd ed. Springer, 2004. ISBN 3-540-43545-X.
- FISHER, W. Digital Video and Audio Broadcasting. A Practical Engineering Guide. 2nd ed. Springer, 2008. ISBN 978-3-540-76357-4.
- ETSI EN 300 744 V1.6.1 (2009-01). Digital Video Broadcasting (DVB), Framing structure, channel coding and modulation for digital terrestrial television. European Standard ETSI, 2009.
- ETSI TR 101 290 V1.2.1 (2001-05). Digital Video Broadcasting (DVB), Measurement guidelines for DVB systems. Technical Report ETSI, 2001.
- ETSI EN 302 304 V1.1.1 (2004-11). Digital Video Broadcasting (DVB), Transmission system for handheld terminals. European Standard ETSI, 2004.
- STUKAVEC, R.; KRATOCHVIL, T. Performance of hierarchical modulation in DVB-T. In Proceedings of the 20th International Conference Radioelektronika 2010. Brno (Czech Republic), 2010, pp. 49-52. ISBN: 978-1-4244-6319-0.
- KRATOCHVIL, T.; STUKAVEC, R. Hierarchical modulation in DVB-T/H mobile TV transmission over fading channels. In Proceedings of the 2008 International Symposium on Information Theory and its Applications (ISITA2008). Auckland (New Zealand), 2008, pp. 1-6. ISBN: 978-1-4244-2069-8.
- KRATOCHVIL, T. Hierarchical modulation in DVB-T/H mobile TV transmission. In Plass, S., Dammann, A., Kaiser S., Fazel, K (eds.). MultiCarrier Systems & Solutions 2009. Lecture Notes in Electrical Engineering. Vol. 41. ISSN 1876-1100. Lecture Notes in Electrical Engineering. Herrsching, Germany: Springer Netherlands, 2009. pp. 334-341. ISBN: 978-90-481-2529-6.

Keywords: Hierarchical modulation, high priority path, low priority path, stream, HP, LP, COFDM, DVB-T/H.

**F. Khateb, J. Vavra, D. Biolek**
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A Novel Current-Mode Full-Wave Rectifier Based on One CDTA and Two Diodes

Precision rectifiers are important building blocks for analog signal processing. The traditional approach based on diodes and operational amplifiers (OpAmps) exhibits undesirable effects caused by limited OpAmp slew rate and diode commutations. In the paper, a full-wave rectifier based on one CDTA and two Schottky diodes is presented. The PSpice simulation results are included.

- FERRI, G., GUERRINI, N. C. Low–Voltage Low–Power CMOS Current Conveyors. Cluwer Academic Publishers, 2003.
- DI CATALDO, G., PALUMBO, G., PENISSI, S. A Schmitt trigger by means of CCII+. Int. Journal of Circuit Theory and Applications, 1995, vol. 23, p. 161–165.
- CICEKOGLU, M. O., KUNTMAN, H. On the design of CCII+ based relaxation oscillator employing single grounded passive element for linear period control. Microelectronics Journal, 1999, vol. 29, p. 993–999.
- ALZAHER, H., TASADDUQ, N. Realizations of CMOS fully differential current followers/amplifiers. In Proc. of ISCAS 2009. Taiwan, 2009, p. 1381–1384.
- BAJER, J., VAVRA, J., BIOLEK, D. A new building block for analog signal processing: current follower/inverter buffered transconductance amplifier. In PRIME 2009 – 5th Int. Conf. on Ph. D. Research in Microelectronics&Electronics. Cork (Ireland), 2009, p. 136–139.
- BIOLEK, D., BIOLKOVA, V., KOLKA, Z., BAJER, J. Singleinput multi-output resistorless current-mode biquad. In Proc. of ECCTD 2009. Antalya (Turkey), 2009, p. 225–228.
- BIOLEK, D., SENANI, R., BIOLKOVA, V., KOLKA, Z. Active elements for analog signal processing: classification, review, and new proposals. Radioengineering, 2008, vol. 17, no. 4, p. 15–32.
- BIOLEK, D., BIOLKOVA, V. Allpass filter employing one grounded capacitor and one active element. Electron. Lett., 2009, vol. 45, no. 16, p. 807–808. DOI: 10.1049/el.2009.0575.
- BHASKAR, D. R., SENANI, R. New FTFN-based grounded-capacitor SRCO with explicit current-mode output and reduced number of resistors. Int. J. Electron. Commun. (AEU), 2005, vol. 59, no. 1, p. 48–51.
- CAM, U., TOKER, A., CICEKOGLU, O., KUNTMAN, H. Current-mode high output impedance sinusoidal oscillator configuration employing single FTFN. Anal. Integr. Circuits Signal Process., 2000, vol. 24, p. 231–238.
- CHANG, C. M., AL–HASHIMI, B. M., CHEN, H. P., TU, S. H., WAN, J. A. Current mode single resistance controlled oscillators using only grounded passive components. Electron. Lett., 2002, vol. 38, p. 1070–1072.
- KUNTMAN, H., CICEKOGLU, O., OZOGUZ, S. A modified third generation current conveyor, its characterization and applications. Frequenz, 2002, vol. 56, p. 47–54.
- SENANI, R., SINGH, V. K., SINGH, A. K., BHASKAR, D. R. Novel electronically controllable current–mode universal biquad filter. IEICE Electronics Express, 2004, vol. 1, no. 14, p. 410–415.
- ABUELMA'ATTI, M. T., BENTRCIA, A. New universal current– mode multiple–input multiple–output OTA–C filter. In Proc. of the 2004 IEEE Asia-Pacific Conf. on CAS. 2004, p. 1037–1040.
- BIOLEK, D., BIOLKOVA, V., KOLKA, Z. Universal current-mode OTA-C KHN biquad. In Proc. of the Int. Conf. ICECS 2007. Venice (Italy), 2007, p. 289–292.
- CICEKOGLU, O., TARIM, N., KUNTMAN, H. Wide dynamic range high output impedance current–mode multifunction filters with dual–output current conveyors. Int. J. Electron. Commun. (AEU), 2002, vol. 56, no. 1, p. 55–60.
- TSUKUTANI, T., SUMI, Y., YABUKI, N. Novel current-mode biquadratic circuit using only plus type DO–DVCCs and grounded passive components. Int. J. of Electronics, 2007, vol. 94, p. 1137– 1146.
- LAOUDIAS, C., PSYCHALINOS, C. Low–voltage CMOS adjustable current mirror. Electron. Lett., 2010, vol. 46, no. 2, p. 124–126.
- ALZAHER, H. A. A CMOS digitally programmable universal current-mode filter. IEEE Transactions on Circuits and Systems – II: Express Briefs, 2008, vol. 55, no. 8, p. 758–762.
- LAWANWISUT, S., SIRIPRUCHYANUN, M. Temperature insensitive/electronically controllable current–mode squarer based on CC–CDBAs. In Proc. of the 1st Int. Conf. on Technical Education (ICTE2009). Bangkok (Thailand), 2010, p. 225–228.
- KUMBUN, J., LAWANWISUT, S., SIRIPRUCHYANUN, M. A temperature-insensitive simple current-mode squarer employing only multiple-output CCTAs. In Proc. of IEEE TENCON 2009. Singapore, p. 1–4.
- TOUMAZOU, C., LIDGEY, F. J., HAIGH, D. G. Analogue IC Design: The current mode approach. IEE Circuits and Systems Series 2. Peter Peregrinus Ltd., 1990.
- CCII01 current conveyor amplifier. Data sheet, LTP Electronics Ltd., Oxford, UK, 1993.
- LIDGEY, F. J., HAYATLEH, K., TOUMAZOU, C. New current– mode precision rectifiers. In Proc IEEE Int. Symp. Circuits and Systems. Chicago (USA), 1993, p. 1322–1325.
- TOUMAZOU, C., LIDGEY, F. J., CHATTONG, S. High frequency current conveyor precision full-wave rectifier. Electron. Lett., 1994, vol. 30, no.10, p. 745–746.
- STIURCA, D. Truly temperature independent current conveyor precision rectifier. Electron. Lett., 1995, vol. 31, no. 16, p. 1302– 1303.
- MANNAMA, V., WILSON, B. Improved biasing error in current-mode absolute value circuits. Proc. of the ECCTD’99. Stresa (Italy), Sept. 1999, p. 655-658.
- TILIUTE, D. E. Full-wave current-mode precision rectifiers using unity-gain cells. Elektronika i Elektrotechnika, 2003, vol. 49, no. 7, p. 26–29.
- TILIUTE, D. E. On the current-mode rectification. Annals of the “Stefan cel Mare”, University of Suceava, Romania, Electrical Section, no. 11, 1999. p. 61–65.
- DUKIC, S. The analysis of full–wave wide–band precision rectifier with modified second type current conveyor. Facta Universitatis (NIS), Ser.: Elec. Energ., 2007, vol. 20, no. 2, p. 215–221.
- GIFT, S.J.G. An improved precision full–wave rectifier. Int. J. Electronics, 2002, vol. 89, no. 3, p. 259–265.
- BIOLEK, D., HANCIOGLU, E., KESKIN, A.U. High–performance current differencing transconductance amplifier and its application in precision current–mode rectification. Int. J. Electron. Commun. (AEU), 2008, vol. 62, no. 2, p. 92–96.
- BIOLEK, D. CDTA – building block for current-mode analog signal processing. In Proceedings of the ECCTD’03. Krakow (Poland), 2003, vol. III, p. 397–400.
- KESKIN, A. U., BIOLEK, D., HANCIOGLU, E., BIOLKOVA, V. Current–mode KHN filter employing current differencing transconductance amplifiers. Int. J. Electron. Commun. (AEU), 2006, vol. 60, no. 6, p. 443–446.
- TANGSRIRAT, W., SURAKAMPONTORN, W. Systematic realization of cascadable current–mode filters using current differencing transconductance amplifiers. Freq., 2006, vol. 60, no. 11–12, p. 241–245.
- PRASAD, D., BHASKAR, D. R., SINGH, A. K. Universal current-mode biquad filter using dual output current differencing transconductance amplifier. Int. J. Electron. Commun. (AEU), 2009, vol. 63, no. 6, p. 497–501.
- UYGUR, A., KUNTMAN, H., ZEKI, A. Multi–input multi–output CDTA–based KHN filter. In Proceedings of ELECO 2005. Bursa (Turkey), 2005, p. 46–50.
- UYGUR, A., KUNTMAN, H. Novel current–mode biquad using a current differencing transconductance amplifier. In Proceedings of Applied Electronics 2005. Pilsen (Czech Republic), 2005, p. 349–352.
- KESKIN, A. U., BIOLEK, D. Current mode quadrature oscillator using current differencing transconductance amplifiers (CDTA). IEE Proceedings on Circuits, Devices and Systems, 2006, vol. 153, no. 3, p. 214 – 218.
- TANGSRIRAT, W., DUMAWIPATA, T., SURAKAMPONTORN, W. Multiple–input single–output current–mode multifunction filter using current differencing transconductance amplifiers. Int. J. Electron. Commun. (AEU), 2007, vol. 61, no. 4, p. 209–214.
- JAIKLA, W., SIRIPRUCHYANUN, M. Current Controlled Current Differencing Transconductance Amplifier (CCCDTA): A new building block and its applications. In Proceedings of the ECTI– CON 2006. Thailand, 2006, p. 348–351.
- JAIKLA, W., SIRIPRUCHYANUN, M., BAJER, J., BIOLEK, D. A simple current–mode quadrature oscillator using single CDTA. Radioengineering, 2008, vol. 17, no. 4, p. 33–40.
- PROKOP, R., MUSIL, V. New modular current devices for true current mode signal processing. Electronics, 2007, vol. 16, no. 4, p. 36–42.
- OPA860. Wide Bandwidth Operational Transconductance Amplifier (OTA) and Buffer. Datasheet, Texas Instruments, SBOS331B, June 2006.
- BIOLEK, D., BAJER, J., BIOLKOVA, V., KOLKA, Z., KUBICEK, M. Z Copy–Controlled Gain–Current Differencing Buffered Amplifier and its applications. Int. Journal of Circuit Theory and Applications, 2010. Published online in Wiley Interscience, DOI: 10.1002/cta.632.
- SPICE model of OPA860 by Texas Instruments (Rev. B – Revised 4/25/06).
- 1PS79SB63 Schottky barrier diode. Data sheet, April 08, 2002, Philips Semiconductors.
- BIOLEK, D., BIOLKOVA, V., KOLKA, Z. AC Analysis of operational rectifiers via conventional circuit simulators. WSEAS Transactions on Circuits and Systems, 2004, vol. 3, no. 10, p. 2291 to 2295.

Keywords: Current-mode rectifier, CDTA.

**R. Sotner, Z. Hrubos, J. Slezak, T. Dostal**
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Simply Adjustable Sinusoidal Oscillator Based on Negative Three-Port Current Conveyors

The paper deals with sinusoidal oscillator employing two controlled second-generation negative-current conveyors and two capacitors. The proposed oscillator has a simple circuit configuration. Electronic (voltage) adjusting of the oscillation frequency and condition of oscillation are possible. The presented circuit is verified in PSpice utilizing macro models of commercially available negative current conveyors. The circuit is also verified by experimental measurements. Important characteristics and drawbacks of the proposed circuit and influences of real active elements in the designed circuit are discussed in detail.

- BIOLEK, D., SENANI, R., BIOLKOVA, V., KOLKA, Z. Active elements for analog signal processing: Classification, Review, and New Proposal. Radioengineering, 2008, vol. 17, no. 4, pp. 15 – 32.
- HERENCSAR, N., VRBA, K., KOTON, J., LATTENBERG, I. The conception of differential-input buffered and transconductance amplifier (DBTA) and its application. IEICE Electronics Express, 2009, vol. 6, no. 6, pp. 329-334.
- HERENCSAR, N., KOTON, J., VRBA, K., MISUREC, J. A novel current-mode SIMO type universal filter using CFTAs. Contemporary Engineering Sciences, 2009, vol. 2, no. 2, pp. 59 to 66.
- TOUMAZOU, C., LIDGEY, F. J., HAIGH, D. G. Analogue IC Design: The Current Mode Approach. London: Peter Peregrinus Ltd., 1990.
- TANGSRIRAT, W. Current-tunable current-mode multifunctional filter based on dual-output current-controlled conveyors. AEU – International Journal of Electronics and Communications, 2007, vol. 61, no. 8, pp. 528-533.
- JAIKLA, W., SIRIPRUCHYANUN, M. Low-component electronically controllable dual-mode universal biquad filter using DOCCCIIs. In Proceedings of Asia-Pacific Conference on Communications 2007, pp. 331-334.
- BIOLEK, D., SIRIPRUCHYANUN, M., JAIKLA, W. CCII and OTA based current-mode universal biquadratic filter. In The Sixth PSU Engineering Conference, May 2008, pp. 238-241.
- WANG. C, ZHAO, Y., ZHANG, Q., DU, S. A new current mode SIMO-type universal biquad employing multi-output current conveyors (MOCCIIs). Radioengineering, 2008, vol. 18, no. 1, pp. 83–88.
- SIRIPRUCHYANUN, M., CHANAPROMMA, C., SILAPAN, P., JAIKLA, W. BiCMOS current-controlled current feedback amplifier (CC-CFA) and its applications. WSEAS Transactions on Electronics, 2008, vol. 5, no. 6, pp. 203-219.
- BIOLEK, D., BIOLKOVA, V., KOLKA, Z. Universal current-mode OTA-C KHN biquad. International Journal of Electronics, Circuits and Systems, 2007, vol. 1, no. 4, pp. 214-217.
- KESKIN, A. U., BIOLEK, D., HANCIOGLU, E., BIOLKOVA, V. Current-mode KHN filter employing current differencing transconductance amplifiers. Int. J. Electronics and Communications, 2006, vol. 60, no. 6, pp. 443-446.
- BIOLEK, D., BIOLKOVA, V., KESKIN, A. U. Current mode quadrature oscillator using two CDTAs and two capacitors. In Proceedings of the 5th Int. Conf. on System Science and Simulation in Engineering. Spain, 2006, pp. 368-370.
- LAHIRI, A. New current-mode quadrature oscillators using CDTA. IEICE Electronics Express, 2009, vol. 6, no. 3, pp. 135 to 140.
- MAHESHWARI, S., KHAN, I. A. Novel single resistor controlled quadrature oscillator using two CDBAs. Journal of Active and Passive Electronic Devices, 2007, vol. 2, pp. 137-142.
- HORNG, J. W. Current conveyors based allpass filters and quadrature oscillators employing grounded capacitors and resistors. Computers and Electrical Engineering, 2005, vol. 31, pp. 81-92.
- CHANG, C. M. Novel current-conveyor-based single-resistance-controlled/voltage-controlled oscillator employing grounded resistors and capacitors. Electronic Letters, 1994, vol. 30, no. 3, pp. 181-183.
- KUMAR, V., PAL, K. Single element controlled sinusoidal oscillators using current conveyors. Journal of Active and Passive Electronic Devices, 2009, vol. 8. pp. 197-202.
- KUMAR, A., VYAS, A. L. A single resistance controlled eight possible oscillator circuits for analog signal processing applications. Academic Open Internet Journal, 2007, vol. 21, pp. 1-7.
- TOKER, A., KUNTMAN, H., CICEKOGLU, O., DISCIGIL, M. New oscillator topologies using inverting second-generation current conveyors. Turk. J. Elec. Engin., 2002, vol. 10, no. 1, pp. 119-129.
- SHEN-IUAN, LIU. Single-resistance-controlled/voltage controlled oscillator using current conveyors and grounded capacitors. Electronic Letters, 1995, vol. 31, no. 5, pp. 337-338.
- AGGARWAL, V. Novel canonic current mode DDCC based SRCO synthesized using a genetic algorithm. Analog Integrated Circuits and Signal Processing, 2004, vol. 40, pp. 83-85.
- SOLIMAN, A. M. Current-mode oscillators using single output current conveyors. Microelectronics Journal, 1998, vol. 29, pp. 907-912.
- SOLIMAN, A. M. Synthesis of grounded capacitor and grounded resistor oscillators. Journal of the Franklin Institute, 1999, vol. 336, pp. 735-746.
- LAHIRI, A. Additional realization of single-element-controlled oscillators using single ICCII-. International Journal of Computer and Electrical Engineering, 2009, vol. 1, no. 3, pp. 303-306.
- PANDEY, N., PAUL, K. A novel electronically tunable sinusoidal oscillator based on CCCII (-IR). Journal of Active and Passive Electronic Devices, 2008, vol. 3, pp. 135-141.
- HORNG, J. W. A sinusoidal oscillator using current-controlled current conveyors. Int. Journal of Electronics, 2001, vol. 88, no. 6, pp. 659-664.
- HORNG, J. W., LIN, S., YANG, CH. Sinusoidal oscillators using current conveyors and grounded capacitors. Journal of Active and Passive Electronic Devices, 2007, vol. 2, pp. 127-136.
- ABUELMAATTI, M. T. New sinusoidal oscillators with fully uncoupled control of oscillation frequency and condition using three CCII+s. Analog Integrated Circuits and Signal Processing, 2000, vol. 24, pp. 253-261.
- KHAN, A. A., BIMAL, S., DEY, K. K., ROY, S. S. Novel RC sinusoidal oscillator using second-generation current conveyor. IEEE Transaction on Instrumentation and Measurement, 2005, vol. 54, no. 6, pp. 2402-2406.
- MARTINEZ, P. A., SABADELL, J., ALDEA, C., CELMA, S. Variable frequency sinusoidal oscillators based on CCII+. IEEE Transaction on Circuits and Systems-I: Fundamental Theory and Applications, 1999, vol. 46, no. 11, pp. 1386-1390.
- KILINC, S., JAIN, V., AGGARWAL, V., CAM, U. Catalogue of variable frequency and single-resistance-controlled oscillators employing a single differential difference complementary current conveyor. Frequenz, 2006, vol. 60, no. 7-8, pp. 142-146.
- SHEN-IUAN, LIU, JIANN-HORNG, TSAY Single-resistance-controlled sinusoidal oscillator using current-feedback-amplifiers. Int. Journal of Electronics, 1996, vol. 80, no. 5, pp. 661-664.
- SHEN-IUAN, LIU, CHUNG-SHINN, Shih., DONG-SHIUH, Wu. Sinusoidal oscillators with single element control using a current-feedback amplifier. Int. Journal of Electronics, 1994, vol. 77, no. 6, pp. 1007-1013.
- GUPTA, S. S., BHASKAR, D. R., SENANI, R. New voltage controlled oscillators using CFOAs. AEU – Int. J. of Electronics and Communications, 2009, vol. 63, no. 3, pp. 209-217.
- BHASKAR, D. R., SENANI, R. New CFOA-based single-element-controlled sinusoidal oscillators. IEEE Transaction on Instrumentation and Measurement, 2006, vol. 55, no. 6, pp. 2014 to 2021.
- SOLIMAN, A. M. Current feedback operational amplifier based oscillators. Analog Integrated Circuits and Signal Processing, 2000, vol. 23, no. 1, pp. 45-55.
- SINGH, V. K., SHARMA, R. K., SINGH, A. K., BHASKAR, D. R., SENANI, R. Two new canonic single-CFOA oscillators with single resistor controls. IEEE Transaction on Circuits and Systems-II: Express Briefs, 2005, vol. 52, no. 12, pp. 860-864.
- CAM, U., TOKER, A., CICEKOGLU, O., KUNTMAN, H. Current-mode high output impedance sinusoidal oscillator configuration employing single FTFN. Analog Integrated Circuits and Signal Processing, 2000, vol. 24, pp. 231-238.
- RANDALL, L. G., SANCHEZ-SINENCIO, E. Active filter design using operational transconductance amplifiers: A tutorial. IEEE Circuits and Devices Magazine, 1985, vol. 1, pp. 20-32.
- DOSTAL, T., AXMAN, V. Biquads based on single negative impedance converter implemented by classical current conveyor. Radioengineering, 2007, vol. 16, no. 3, pp. 96-102.
- Analog Devices. Monolithic Op Amp AD 844, 16 p. [Online] Available at: http://www.analog.com
- Intersil (Elantec). EL 2082CN Current-Mode Multiplier, 1996, 16 p. [Online] Available at: http://www.intersil.com

Keywords: Current conveyors, electronic adjusting, sinusoidal oscillator.

**R. Pandey, M. Gupta**
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FGMOS Based Voltage-Controlled Grounded Resistor

This paper proposes a new floating gate MOSFET (FGMOS) based voltage-controlled grounded resistor. In the proposed circuit FGMOS operating in the ohmic region is linearized by another conventional MOSFET operating in the saturation region. The major advantages of FGMOS based voltage-controlled grounded resistor (FGVCGR) are simplicity, low total harmonic distortion (THD), and low power consumption. A simple application of this FGVCGR as a tunable high-pass filter is also suggested. The proposed circuits operate at the supply voltages of +/-0.75 V. The circuits are designed and simulated using SPICE in 0.25-µm CMOS technology. The simulation results of FGVCGR demonstrate a THD of 0.28% for the input signal 0.32 V_{pp} at 45 kHz, and a maximum power consumption of 254 µW.

- YAN, S., SANCHEZ-SINENCIO, E. Low voltage analog circuit design techniques: A tutorial. IEICE Trans. Analog Integrated Circuits and Systems, 2000, vol. E00–A, no. 2, p. 1-17.
- SANCHEZ-SINENCIO, E., ANDREOU, A. G. Low Voltage/Low Power Integrated Circuits and Systems. New York: IEEE Press, 1999.
- RAMIREZ-ANGULO, J., CHOI, S. C., ALTAMIRANO, G. G. Low voltage circuits building blocks using multiple input floating gate transistors. IEEE Trans. Circuits Syst. –I, 1995, vol. 42, no. 11, p. 971-974.
- SHARMA, S., RAJPUT, S. S., MANGOTRA, L. K., JAMUAR, S. S. FGMOS based wide range low voltage current mirror and its applications. In Proceedings of the APCCAS-2002/ IEEE. 2000, vol. 2, p. 331-334.
- LIMING, Y., EMBADI, S. H. K., SANCHEZ-SINENCIO, E. A floating gate MOSFET D/A converter. In Proceedings of IEEE Int. Symp. Circuits Systems, Hong Kong, 1997, p. 409-412.
- PANDEY, R., GUPTA, M. A new FMOS voltage-controlled resistor. In Proceedings of IEEE International Conference on Intelligent and Advanced Systems. Malaysia, 2007, p. 1392-1395.
- POPA, C. Programmable CMOS active resistor using computational circuits. In Proceedings of International Semiconductor Conference - CAS 2008/IEEE, 2008, vol. 2, p. 389-392.
- PANDEY, R., GUPTA, M. A novel voltage-controlled grounded resistor using FGMOS technique. In Proceedings of IEEE International Conference on Multimedia, Signal Processing and Communication Technologies, 2009, p. 16-19.
- GUPTA, M., PANDEY, R. FGMOS based low-voltage tunable floating resistor. Journal of Active and Passive Electronic Devices, to be published.
- BERG, Y., LANDE, T. S. Programmable floating gate MOS logic for low-power operation. In Proceedings of IEEE Int. Symp. Circuits Systems-ISCAS-97, Hong Kong, 1997, p. 1792-1795.
- LEE, B. W., SHEU, B. J., YANG, H. Analog floating gatesynapses for general purpose VLSI neural computation. IEEE Trans. Circuits Syst., 1991, vol. 38, p. 654-657.
- RAMIREZ-ANGULO, J., CHOI, S. C., ALTAMIRANO, G. G. Low voltage circuits building blocks using multiple input floating gate transistors. IEEE Trans. Circuits Syst. -I, 1995, vol. 42, no. 11, p. 971-974.
- WANG, Z. Novel voltage-controlled grounded Electronics Letters, 1990, vol. 26, no. 20, p. 1711-1712. resistor.
- HAN, S., PARK, S. B. Voltage-controlled linear resistor by two MOS transistors and its application to active RC filter MOS integration. In Proceedings of IEEE, 1984, vol. 72, p. 1655-1657.
- WILSON, G., CHAN, P. K. Novel voltage-controlled grounded resistor. Electronics Letters, 1989, vol. 25, no. 25, p.1725-1726.
- SENANI, R. Analysis, synthesis and design of new types of RC-active sinusoidal oscillators: Part I. Frequenz: Journal of Telecommunications, 1988, vol. 42, no. 8, p. 223-228.
- SENANI, R. Analysis, synthesis and design of new types of RC-active sinusoidal oscillators: Part II. Frequenz: Journal of Telecommunications, 1988, vol. 42, no. 9, p. 251-256.
- BABANEZHAD, J. N., TEMES, G. C. A linear NMOS depletion resistor and its application in an integrated amplifier. IEEE Journal of Solid-State Circuits, 1984, vol. SC-19, no. 6, p.932-938.
- INOUE, T., NAKANE, H., FUKUJU, Y., SANCHEZ-SINENCIO, E. A Design of a low-voltage current-mode fully-differential analog CMOS integrator using FG-MOSFETs and its implementation. Analog Integrated Circuits and Signal Processing, 2002, vol. 32, p. 249–256.
- RODRIGUEZ-VILLEGAS, E., BARNES, H. Solution to trapped charge in FGMOS transistors. Electronics Letters, 2003, vol. 39, no. 19, p. 1416 – 1417.

Keywords: Floating gate MOSFETs, low-voltage, voltage-controlled grounded resistor, Spice.

**M. S. Khan, M. S. Awan, S. Sheikh Muhammad, M. Faisal, Marzuki, F. Nadeem, E. Leitgeb**
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Probabilistic Model for Free-Space Optical Links Under Continental Fog Conditions

The error characteristics of a free-space optical (FSO) channel are signiﬁcantly different from the ﬁber based optical links and thus require a deep physical understanding of the propagation channel. In particular different fog conditions greatly inﬂuence the optical transmissions and thus a channel model is required to estimate the detrimental fog effects. In this paper we shall present the probabilistic model for radiation fog from the measured data over a 80 m FSO link installed at Graz, Austria. The fog events are classiﬁed into thick fog, moderate fog, light fog and general fog based on the international code of visibility range. We applied some probability distribution functions (PDFs) such as Kumaraswamy, Johnson SB and Logistic distribution, to the actual measured optical attenuations. The performance of each distribution is evaluated by Q-Q and P-P plots. It is found that Kumaraswamy distribution is the best ﬁt for general fog, while Logistic distribution is the optimum choice for thick fog. On the other hand, Johnson S_{B} distribution best ﬁts the moderate and light fog related measured attenuation data. The difference in these probabilistic models and the resultant variation in the received signal strength under different fog types needs to be considered in designing an efﬁcient FSO system.

- AHARONOVICH, M., ARNON, S. Performance improvement of optical wireless communication through fog with a decision feedback equalizer. J. Opt. Soc. Am, 2005, vol. 22, p. 1646-54.
- LEITGEB, E., et al, Current optical technologies for wireless access. In Proceeding of ConTel 2009, Zagreb, Croatia, 2009, p. 7-18.
- ZHU, X., KAHN, J. M. Free-space optical communication through atmospheric turbulence channels. IEEE Trans. Commun, 2002, vol. 50, no. 8, p. 1293-1300.
- EPPLE, B. Simpliﬁed channel model for simulation of free-space optical communications. J. OPT. COMMUN. NETW, 2010, vol. 2, no. 5, p. 293-304.
- BISWAS, A., LEE, S. Ground-to-ground optical communications demonstration. Jet Propulsion Laboratory, Pasadena, CA, Telecommunications and Mission Operations Progress, May 2000, TMO Progress Report 42-141, p. 1-31.
- STRICKLAND, B. R., LAVAN, M. J., WOODBRIDGE, E., CHAN, V. Effects of fog on the bit-error rate of a free-space laser communication system. Applied Optics, 1999, vol. 38, p. 424-431.
- GIGGENBACH, D., HENNIGER, H., PERLOT, N., DAVID, F. Multiplewavelength free-space laser communications. In Proc. of SPIE, San Jose, CA, USA, 2003, vol. 4975, p. 12-19.
- ACAMPORA, A. Last mile by laser. Scientiﬁc American, 2002, p. 48-53.
- SHETTLE, E. P. Models of aerosols, clouds, and precipitation for atmospheric propagation studies. In Proceedings of Atmospheric Propagation in the UV, Visible, IR, and MM Wave Region and Related System Aspects, Copenhagen, Denmark, AGCARD, 1989, vol. 454, p. 15.1-15.13.
- MUHAMMAD, S. S., AWAN, M. S., REHMAN, A. PDF estimation and liquid water content based attenuation modeling for fog in terrestrial FSO links. Radioengineering, 2010, vol. 19, no. 2, p. 228-236.
- MOHAMMAD, S. S., FLECKER, B., LEITGEB, E., GEBHART, M. Characterization of fog attenuation in terrestrial free space optical links. Journal of Optical Engineering, 2007, vol. 46, no. 6, p. 066001(1-10).
- KHAN, M. S., AWAN, M. S., LEITGEB, E., NADEEM, F., HUSSAIN, I. Selecting a distribution function for optical attenuation in dense continental fog conditions. In Proceeding of ICET, Islamabad, Pakistan, 2009, p. 142-147.
- AWAN, M. S., NEBULONI, R., CAPSONI, C., CSURGAIHORVTH, L., MUHAMMAD, S. S., LEITGEB, E., NADEEM, F., KHAN, M. S. Prediction of drop size distribution parameters for optical wireless communications through moderate continental fog. International Journal on Satellite Communications and Networks, 2010.
- KRUSE, P. W., McGLAUCHLIN, L. D., McQUISTAN, R. B. Elements of Infrared Technology- Generation, Transmission, and Detection. J. Wiley and Sons, 1962.
- JONES, M. C. Kumaraswamys distribution: A beta-type distribution with some tractability advantages. Statistical Methodology, 2009, vol. 6, p. 70-81.
- BOWLING, S. R., KHASAWNEH, M. T. , KAEWKUEKOOL, S., CHO, B. R. A logistic approximation to the cumulative normal distribution. Journal of Industrial Engineering and Management, 2009, vol. 2, no. 1, p. 114-127.
- FLYNN, M. R. Fitting human exposure data with the johnson sb distribution. Journal of Exposure Science and Environmental Epidemiology, 2006, vol. 16, p. 56-62.
- GILCHRIST, W. G. Statistical Modelling with Quantile Functions. CHAPMAN and HALL/CRC, 2000.
- HOLMGREN, E. B. The p-p plot as a method for comparing treatment effects. Journal of the American Statistical Association, 1995, vol. 90, no. 429, p. 360-365.

Keywords: Free Space Optics (FSO), optical attenuations, Mie scattering, Probability Density Function (PDF), visibility, channel modeling.

**O. Kucera**
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Author's comment on: "Electrical Analogy to an Atomic Force Microscope"

In [1] I used assumptions which proved to be wrong in further research. Corrections are given in this comment.

- KUCERA, O. Electrical analogy to an atomic force microscope. Radioengineering, 2010, vol. 19, no. 1, p. 168 - 171.
- GITTES, F., SCHMIDT, C.F. Thermal noise limitations on micromechanical experiments. European Biophysics Journal, 1998, vol. 27, n. 1, p. 75 - 81.

Keywords: Atomic Force Microscopy, electrical mechanical analogs, circuit theory