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Search Results: 1 - 10 of 297299 matches for " J. Drinovsky "
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Estimation of EMI Filter Performance for the "Worst Case" System
J. Drinovsky,J. Svacina
Radioengineering , 2006,
Abstract: This paper deals with the performance problem of the EMC filters. The core of this problem in EMC filter is the uncertainty of impedances that are connected to the input and output of a filter. In addition, an estimation technique is presented that gives approximate insertion loss of the filter. The performance of this technique was tested on several filters and the data obtained were checked by insertion loss measurement. The heart of the matter is based on the L C equivalent circuits, which are described by Y parameters. The estimation gives pretty good results for the 0.1 /100 and vice-versa systems and also for other systems. Also discussed are system configurations with the ” (delta) and (Y) star topologies of terminating impedances which better approximate the real situation on the input and output terminals of filter.
Evolutionary Synthesis of Fractional Capacitor Using Simulated Annealing Method
J. Slezak,T. Gotthans,J. Drinovsky
Radioengineering , 2012,
Abstract: Synthesis of fractional capacitor using classical analog circuit synthesis method was described in [6]. The work presented in this paper is focused on synthesis of the same problem by means of evolutionary method simulated annealing. Based on given desired characteristic function as input impedance or transfer function, the proposed method is able to synthesize topology and values of the components of the desired analog circuit. Comparison of the results given in [6] and results obtained by the proposed method will be given and discussed.
Potential Worst-case System for Testing EMI Filters Tested on Simple Filter Models
J. Drinovsky,J. Svacina,Z. Raida
Radioengineering , 2008,
Abstract: This paper deals with the approximate worst-case test method for testing the insertion loss of the EMI filters. The systems with 0.1 and 100 impedances are usually used for this testing. These systems are required by the international CISPR 17 standard. The main disadvantage of this system is the use of two impedance transformers. Especially the impedance transformer with 0.1 output impedance is not easy to be produced. These transformers have usually narrow bandwidth. This paper discusses the alternative system with 1 and 100 impedances. The performance of these systems was tested on several filters ¢ € models and the obtained data are depicted, too. The performance comparison of several filters in several systems is also included. The performance of alternate worst-case system is discussed in the conclusion.
Simple Models of EMI Filters for Low Frequency Range
J. Drinovsky,J. Svacina,Z. Raida
Radioengineering , 2008,
Abstract: This paper deals with mathematical simulations of EMI filters ¢ € performance. These filters are commonly used for the suppressing of electromagnetic interference which penetrates through the power supply networks. The performance of these filters depends on terminating impedances which are plugged to the inputs and outputs clamps of the EMI filters. This paper describes the method by which it is possible to calculate the insertion loss of the filters. The method is based on the modified nodal voltage method. The circuitry of the EMI filters is used for their description. The effect of spurious components is not taken into account. The filter itself is described by set of admittance parameters, which makes the presented method more universal. The calculated results were compared with measured data of several filters for several impedance combinations. Different test setups, like asymmetrical, symmetrical, etc. were taken into account. The simplicity and accuracy of the presented method is discussed in the conclusion. The achieved accuracy is on high level. The described method is universal, but for filters with more than one current compensated inductor, the mentioned method is complicated. The size of the final equation for calculating the insertion loss rapidly increases with the number of current compensated inductors.
Multi-Objective Self-Organizing Migrating Algorithm: Sensitivity on Controlling Parameters
P. Kadlec,Z. Raida,J. Drinovsky
Radioengineering , 2013,
Abstract: In this paper, we investigate the sensitivity of a novel Multi-Objective Self-Organizing Migrating Algorithm (MOSOMA) on setting its control parameters. Usually, efficiency and accuracy of searching for a solution depends on the settings of a used stochastic algorithm, because multi-objective optimization problems are highly non-linear. In the paper, the sensitivity analysis is performed exploiting a large number of benchmark problems having different properties (the number of optimized parameters, the shape of a Pareto front, etc.). The quality of solutions revealed by MOSOMA is evaluated in terms of a generational distance, a spread and a hyper-volume error. Recommendations for proper settings of the algorithm are derived: These recommendations should help a user to set the algorithm for any multi-objective task without prior knowledge about the solved problem.
Estimation of the EMI Filter Circuitry from the Insertion Loss Characteristics
Z. Kejik,J. Drinovsky,V. Ruzek
Radioengineering , 2010,
Abstract: The paper deals with the EMI filter models for the calculation of the insertion loss characteristics. The insertion loss is in fact the basic EMI filter property. Unfortunately it is not easy to precisely define and measure this parameter in a wide frequency range due to variability of terminating impedances. The uncertainty of the potential impedance termination really complicates the measurements and also comparison of the performance of filters. A model with spurious components is introduced in this paper. The procedure model design is also added up. The spurious components make together with the real ones form resonant circuits. The resonance frequencies make breakages in the insertion loss characteristic. Their resonance frequencies were identified by the analysis of equivalent circuits of the filter for different measuring systems. The calculation of the values of spurious components, based on knowledge of resonance frequencies, is mentioned at the end of the paper.
Insertion Loss Estimation of EMI Filters in Unmatched Input/Output Impedance System
J. Drinovsky,Z. Kejik,V. Ruzek,J. Zachar
Radioengineering , 2011,
Abstract: One of the problems in the design of powerline EMI filters is the uncertainty and ambiguity of their source/load impedances which results in breach of expected filter parameters in a real installation. The paper presents a simple technique for prediction of insertion loss limit values of EMI filters working in arbitrary unmatched mains line impedance systems.
New components of the mercury’s perihelion precession  [PDF]
J. J. Smulsky
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34034
Abstract: The velocity of perihelion rotation of Mercury's orbit relatively motionless space is computed. It is prove that it coincides with that calculated by the Newtonian interaction of the planets and of the compound model of the Sun’s rotation.
Simple General Purpose Ion Beam Deceleration System Using a Single Electrode Lens  [PDF]
J. Lopes, J. Rocha
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33014
Abstract: Ion beam deceleration properties of a newly developed low-energy ion beam implantation system were studied. The objective of this system was to produce general purpose low-energy (5 to 15 keV) implantations with high current beam of hundreds of μA level, providing the most wide implantation area possible and allowing continuously magnetic scanning of the beam over the sample(s). This paper describes the developed system installed in the high-current ion implanter at the Laboratory of Accelerators and Radiation Technologies of the Nuclear and Technological Cam-pus, Sacavém, Portugal (CTN).
Constraints on velocity anisotropy of spherical systems with separable augmented densities
J. An
Physics , 2011, DOI: 10.1088/0004-637X/736/2/151
Abstract: If the augmented density of a spherical anisotropic system is assumed to be multiplicatively separable to functions of the potential and the radius, the radial function, which can be completely specified by the behavior of the anisotropy parameter alone, also fixes the anisotropic ratios of every higher-order velocity moment. It is inferred from this that the non-negativity of the distribution function necessarily limits the allowed behaviors of the radial function. This restriction is translated into the constraints on the behavior of the anisotropy parameter. We find that not all radial variations of the anisotropy parameter satisfy these constraints and thus that there exist anisotropy profiles that cannot be consistent with any separable augmented density.
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