Identyfikatory
Warianty tytułu
Adaptive time - frequency analysis of a non-stationary measuring signal
Języki publikacji
Abstrakty
W artykule zaprezentowano wirtualny analizator czas-częstotliwość zaprojektowany w środowisku programowania LabVIEW, w którym zaimplementowano metodę adaptacyjną analizy czasowo-częstotliwościowej opartą na algorytmie pogoni za dopasowaniem (ang. matching pursuit MP). Przedstawiono wyniki analiz sygnału pomiarowego, reprezentującego poziom natężenia wolnozmiennego pola magnetycznego, zarejestrowanego w otoczeniu okrętowych odbiorników dużej mocy.
In the paper there is presented a virtual time-frequency analyzer designed with use of LabVIEW programming environment, in which there is implemented an adaptive method of time-frequency analysis based on the matching pursuit algorithm (Fig. 1). Matching pursuit (MP) is an iterative algorithm using a redundant dictionary of functions in order to select the functions, which best match the signal components. Thanks to the varying window size and modulation frequency, MP enables an adaptive (i.e. fitting local structures) signal representation. Linear Gaussian chirplets were used as the elementary functions. Measuring signals are the sum of time-limited waveforms occurring at different time instants and having different bandwidths (Fig. 2). The application of the time-frequency adaptive method certainly provides a significantly better joint time-frequency resolution in comparison with other quadratic joint time-frequency distributions. The analysis of the measuring signal of low-varying magnetic field recorded in the surroundings of high power ship receivers is presented (Figs. 3, 4, 5). Estimation of the usefulness of the implemented method for measurements of the non-stationary magnetic field intensity of ship electromagnetic environment is performed. It is shown that the adaptive time-frequency-domain representation of the magnetic field intensity was successfully applied to determine, with some time resolution, the moments when the analyzed signal components of different frequencies occurred.
Wydawca
Czasopismo
Rocznik
Tom
Strony
934--936
Opis fizyczny
Bibliogr. 9 poz., rys., wzory
Twórcy
autor
- Akademia Morska w Gdyni, Katedra Telekomunikacji Morskiej, ul. Morska 83,81-200 Gdynia, palbeata@am.gdynia.pl
Bibliografia
- [1] Pałczyńska B.: Spectral analysis of nonstationary low-frequency magnetic-field emissions from ship’s power frequency converters. Conference Proceedings of IEEE 6th International Conference-Workshop Compatibility in Power Electronics, CPE2009, Badajoz, Spain 2009, pp. 375-380.
- [2] Zieliński T. P.: Cyfrowe przetwarzanie sygnałów. Od teorii do zastosowań. WKŁ, Warszawa 2005.
- [3] Durka P. J: Miedzy czasem a częstością: elementy współczesnej analizy sygnałów, 1999-2004. http://brain.fuw.edu.pl/~durka/as/ (luty 2007).
- [4] Cohen L.: Time - frequency analysis. Practice Hall Inc., New Jersey, 1995.
- [5] Allen R. L., Mills D. W.: Signal analysis. Time, frequency, scale, and structure. Willey-IEEE Press, 2004.
- [6] Mallat S. G., Zhang Z.: Matching pursuit with time frequency dictionaries. IEEE Trans. Signal Process., 41 (12), (1993), pp. 3397-3415.
- [7] Qinye Yin, Shie Qian, Aigang Feng: A Fast Refinement for Adaptive Gaussian Chirplet Decomposition. IEEE Trans. Signal Processing, vol. 50, Nr 6, June. 2003, pp. 1298-1306.
- [8] LabVIEW - Advanced Signal Processing Toolkit - Time Frequency Analysis Tools. User Manual, National Instrument, 2005.
- [9] Pałczyńska B., Kroplewski Ł.: Analiza czasowo-częstotliwościowa niestacjonarnego sygnału pomiarowego. Przegląd Elektrotechniczny (Electrical Review), R. 85 NR 2/2009, ss. 37-40.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BSW4-0127-0008