2004/1

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    Contribution to the Chebyshev Approximations of the Normalized Low-Pass Prototype
    (Společnost pro radioelektronické inženýrství, 2004-04) Laipert, Milos; Vlcek, Miroslav; Vrbata, Jan
    The standard approximation algorithms are well described in the literature, but some equiripple approximations are described with some deficiencies. Especially Chebyshev and inverse Chebyshev approximations are often wrongly interpreted or implemented. In this paper, we propose all formulas for computing Chebyshev approximations in a standard form. Transformations, which are necessary for circuit implementation, are presented in the analytical form too.
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    The Performance of W-CDMA Highways Infostations
    (Společnost pro radioelektronické inženýrství, 2004-04) Taha-Ahmed, Bazil; Calvo-Ramon, Miguel; de Haro-Ariet, Leandro
    The expected value of the signal to noise ratio of W-CDMA infostations is derived. A model of 5 cells is used to analyze the system performance. The infostations are assumed to exist in rural zones. The performance of the infostations is studied for different breakpoint distances, different infostations separation, a different number of users for each infostation and for different bit rate.
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    Estimator Comparison of the Nakagami-m Parameter and its Application in Echocardiography
    (Společnost pro radioelektronické inženýrství, 2004-04) Kolar, Radim; Jirik, Radovan; Jan, Jiri
    This article deals with the comparison of various estimators of the m parameter from the Nakagami distribution. This kind of distribution has been used in many engineering applications and we present another possible application in biomedical engineering, particularly the ultrasound tissue characterization in the echocardiographic application. Matlab 6.5 was used as a proper tool for fast and efficient scientific research.
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    Improvement of Watson's DVQ Metric
    (Společnost pro radioelektronické inženýrství, 2004-04) Simik, Richard
    An improvement of Watson's DVQ (Digital Video Quality) metrics is introduced. This metric was chosen for its easy implementation caused by using DCT (Discrete Cosine Transform) for video decomposition into spatial channels. The metric is upgraded by segmentation tool. This tool is used for weighting the masked differences.
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    3D Motion Estimation and Texturing of Human Head Model
    (Společnost pro radioelektronické inženýrství, 2004-04) Mihalik, Jan; Michalcin, Viktor
    This paper deals with 3D motion estimation of the wire frame head model on the basis of the analysis of the parameters of 3D global motion of the real human head for each frame of videosequence. The proposed algorithm of 3D global motion estimation is given by solution of 6 linear equations for three extracted feature points of the real human head in each frame. Next there is presented an algorithm of texturing of 3D wire frame model of human head after its estimated global motion. Texturing is carried out by two dimensional affine transform directly in synthesized frames. Both proposed algorithms can achieve very low bit rate in model based image coding.