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Radojicic V.,University of Belgrade | Markovic G.,University of Belgrade | Jankovic M.,Republic Agency for Electronic Communications | Draskovic B.,Telekom Srbija
Promet - Traffic - Traffico | Year: 2012

This paper proposes a modification of traffic forecast model generated by residential and small business (SOHO, Small Office Home Office) users. The model includes forecasted values of different relevant factors and competition on broadband market. It allows forecasting the number of users for various broadband technologies and interaction impact of long-standing technologies as well as the impact of the new technology entrant on the market. All the necessary parameters are evaluated for the Serbian broadband market. The long-term forecasted results of broadband traffic are given. The analyses and evaluations performed are important inputs for the transport network resources planning.

Pavlovic V.D.,University of Nis | Ilic A.D.,Republic Agency for Electronic Communications | Cvetkovic Z.Z.,University of Nis
2013 21st Telecommunications Forum Telfor, TELFOR 2013 - Proceedings of Papers | Year: 2013

The paper proposes a precise analytical method for finding the explicit expression for the characteristic function of filters applicable to the design of RC active filters. The adverse parasite effects of limited finite gain-bandwidth product of operational amplifiers are decreased by using filters with the low pass-band attenuation. The new class of continual filter functions generated by analytical method by extremal Christoffel-Darboux formula for orthogonal Gegenbauer polynomials has two parameters, the filter order, n, and the real free parameter, ν, provides a wide range of the amplitude responses, [5]. In this paper, a detailed analysis of attenuation in the bandwidth and insertion loss around the stop-band cut-off frequency, ωcs, are carried out using 3D plots on the example of the filter function of the 12-th order. © 2013 IEEE.

Milutinovic V.,Republic Agency for Electronic Communications | Cvetkovic T.,Republic Agency for Electronic Communications | Milovanovic B.,University of Nis | Doncov N.,University of Nis
2011 10th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services, TELSIKS 2011 - Proceedings of Papers | Year: 2011

In this paper an influence of aperture spacing and excitation parameters on shielding properties of enclosure is analyzed. Apertures are represented by two groups of two circular or two rectangular apertures placed on adjacent enclosure walls. The following effects are considered: change of distance between apertures either in horizontal or vertical directions and change of plane wave excitation parameters (polarization, elevation and azimuth). In addition, the impact of internal excitation, represented by a wire source inside the enclosure, on the outside environment is analysed for different apertures placement on front enclosure wall. © 2011 IEEE.

Milutinovic V.,Republic Agency for Electronic Communications | Cvetkovic T.,Republic Agency for Electronic Communications | Doncov N.,University of Nis | Milovanovic B.,University of Nis
Radioengineering | Year: 2013

In this paper, circuital and numerical models of metal enclosure with apertures are considered for the purpose of accurate shielding effectiveness calculation. An improved circuital model is presented to account for the presence of receiving dipole antenna which is often used in practice to measure the level of electromagnetic field at selected points inside the enclosure. Receiving antenna of finite dimensions could significantly change the EM field distribution inside the enclosure and thus affect the results for SE. TLM method incorporating wire node is used to create a numerical model. Both models are compared in terms of their ability to account for receiving antenna impact on shielding effectiveness of rectangular enclosure with aperture. In addition, comparison of both models is carried out for the case when an array of apertures with different aperture separation is present on one of the enclosure walls whereby the numerical TLM model is additionally enhanced with compact air-vent model.

Cvetkovic T.,Republic Agency for Electronic Communications | Milutinovic V.,Republic Agency for Electronic Communications | Doncov N.,University of Nis | Milovanovic B.,University of Nis
Applied Computational Electromagnetics Society Journal | Year: 2014

This paper deals with an impact of receiving antenna placed in a metal enclosure on an electromagnetic field distribution within the enclosure, and thus on its shielding effectiveness. In an experimental setup, a frequently used tool for measuring the electromagnetic field level at certain points within the enclosure is a dipole antenna connected to a measuring instrument via a coaxial cable. For modeling a coupling between the electromagnetic field and antenna in the protective enclosure we use the Transmission-Line Matrix (TLM) method, enhanced with the compact wire model. The numerical model is verified through comparison with the available experimental results and then used to investigate the influence of physical dimensions of dipole antenna and its cable connection on the detected level of shielding effectiveness. © 2014 ACES.

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