2006/4

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    Problem of Bundled Two-Wire Cable of Tested Equipment in Emission Measurement
    (Společnost pro radioelektronické inženýrství, 2006-12) Bittera, Miki; Smiesko, Viktor; Kovac, Karol
    Many factors that influence radiated emission measurement exist. Except of factors relative to measuring chain \"test site - antenna - receiver\" there are some factors caused by operating personnel like inappropriate configuration of tested equipment, etc. Tested equipments contain generally attached cables of different length; the longer ones shall be shortened by folding into a bundle. The aim of this paper is to analyze the behavior of such cables and its influence on results of radiated emission measurement.
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    Estimation of EMI Filter Performance for the \"Worst Case\" System
    (Společnost pro radioelektronické inženýrství, 2006-12) Drinovsky, Jiri; Svacina, Jiri
    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 Ω/100 Ω and vice-versa systems and also for other systems. Also discussed are system configurations with the Δ (delta) and (Y) star topologies of terminating impedances which better approximate the real situation on the input and output terminals of filter.
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    Comparative Performance Analysis of Three Algorithms for Principal Component Analysis
    (Společnost pro radioelektronické inženýrství, 2006-12) Landqvist, Ronnie; Mohammed, Abbas
    Principal Component Analysis (PCA) is an important concept in statistical signal processing. In this paper, we evaluate an on-line algorithm for PCA, which we denote as the Exact Eigendecomposition (EE) algorithm. The algorithm is evaluated using Monte Carlo Simulations and compared with the PAST and RP algorithms. In addition, we investigate a normalization procedure of the eigenvectors for PAST and RP. The results show that EE has the best performance and that normalization improves the performance of PAST and RP algorithms, respectively.
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    Methods for High Power EM Pulse Measurement
    (Společnost pro radioelektronické inženýrství, 2006-12) Drexler, Petr; Fiala, Pavel
    There are some suitable methods for the measurement of ultra-short solitary electromagnetic pulses that can be generated by high power pulsed generators. The measurement methods properties have to correspond to the fact whether we want to measure pulses of voltage, current or free-space electromagnetic wave. The need for specific measurement methods occurred by the development of high power microwave pulse generator. Applicable methods are presented in this paper. The method utilizing Faraday\'s induction law allows the measurement of generated current. For the same purpose the magneto-optic method can be utilized, with its advantages. For measurement of output microwave pulse of the generator the calorimetric method was designed and realized.
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    Modeling and Optimizing Antennas for Rotational Spectroscopy Applications
    (Společnost pro radioelektronické inženýrství, 2006-12) Lukes, Zbynek; Lacik, Jaroslav; Raida, Zbynek
    In the paper, dielectric and metallic lenses are modeled and optimized in order to enhance the gain of a horn antenna in the frequency range from 60 GHz to 100 GHz. Properties of designed lenses are compared and discussed. The structures are modeled in CST Microwave Studio and optimized by Particle Swarm Optimization (PSO) in order to get required antenna parameters.