2006/1

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Now showing 1 - 5 of 9
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    Motion Compensated Video Compression with 3D Wavelet Transform and SPIHT
    (Společnost pro radioelektronické inženýrství, 2006-04) Enyedi, Balazs; Konyha, Lajos; Fazekas, Kalman
    The following paper introduces a low bitrate video coding method on the basis of 3D motion compensated wavelet transform and SPIHT algorithm. In contrast to the conventional algorithms applying motion compensation and differential coding, here wavelet transform is used to exploit the opportunities of time redundancy. For coefficient collection, the 3D version of SPIHT algorithm was selected from the various procedures developed for wavelet transform. Motion vectors are compressed, too (also by wavelet transform), therefore the time and spatial redundancy of coding is exploited here as well. These procedures result in effective video compressing and can easily be aligned to the MPEG4 standard.
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    FPGA Based Test Module for Error Bit Evaluation in Serial Links
    (Společnost pro radioelektronické inženýrství, 2006-04) Kolouch, Jaromir
    A test module for serial links is described. In the link transmitter, one module generates pseudorandom pulse signal that is transmitted by the link. Second module located in the link receiver generates the same signal and compares it to the received signal. Errors caused by the signal transmission can be then detected and results sent to a master computer for further processing like statistical evaluation. The module can be used for long-term error monitoring without need for human operator presence.
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    Lattice RLS for Nonstationary Signal Processing
    (Společnost pro radioelektronické inženýrství, 2006-04) Djigan, Victor I.
    The paper presents the modification of lattice RLS adaptive filtering algorithms for the case of nonstationary signal processing. The modification includes the using of sliding window and dynamic regularization in the adaptive filter correlation matrix estimation. The algorithms can be implemented by means of sequential or parallel computations. Based on sequential computations, 30 regularized prewindowed, sliding widow and regularized sliding window lattice RLS algorithms were developed. A family of the same algorithms with parallel computations includes 21 units. Lattice algorithms are developed for the application in single-channel adaptive filters with complex-valued weights. Some computation procedures of the algorithms are listed. The results of the algorithm simulation are also presented.
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    Robust GPS Satellite Signal Acquisition Using Lifting Wavelet Transform
    (Společnost pro radioelektronické inženýrství, 2006-04) Djebouri, Djamel; Djebbari, Ali; Djebbouri, Mohamed
    A novel GPS satellite signal acquisition scheme that utilizes lifting wavelet to improve acquisition performance is proposed. Acquisition in GPS system is used to calculate the code phase (or shift) and find the pseudo-range, which is used to calculate the position. The performance of a GPS receiver is assessed by its ability to precisely measure the pseudo-range, which depends on noise linked to the signals in the receiver’s tracking loops. The level of GPS receiving equipment system noise determines in part how precisely pseudo-range can be measured. Our objective, in this paper, is to achieve robust real-time positioning with maximum of accuracy in the presence of noise. Robust positioning describes a positioning system\'s ability to maintain position data continuity and accuracy through most or all anticipated operational conditions. In order to carry out a robust less complex GPS signals acquisition system and to facilitate its implementation, a substitute algorithm for calculating the convolution by using lifting wavelet decomposition is proposed. Simulation is used for verifying the performance which shows that the proposed scheme based lifting wavelet transform outperforms both FFT search and signal decimation schemes in the presence of a hostile environment.
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    High Resolution of the ECG Signal by Polynomial Approximation
    (Společnost pro radioelektronické inženýrství, 2006-04) Jurko, Stefan; Rozinaj, Gregor
    Averaging techniques as temporal averaging and space averaging have been successfully used in many applications for attenuating interference [6], [7], [8], [9], [10]. In this paper we introduce interference removing of the ECG signal by polynomial approximation, with smoothing discrete dependencies, to make up for averaging methods. The method is suitable for low-level signals of the electrical activity of the heart often less than 10 m V. Most low-level signals arising from PR, ST and TP segments which can be detected eventually and their physiologic meaning can be appreciated. Of special importance for the diagnostic of the electrical activity of the heart is the activity bundle of His between P and R waveforms. We have established an artificial sine wave to ECG signal between P and R wave. The aim focus is to verify the smoothing method by polynomial approximation if the SNR (signal-to-noise ratio) is negative (i.e. a signal is lower than noise).