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Wyszukujesz frazę "frequency drift" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Frequency based islanding detection methods in power electronic converters
Autorzy:
Dmitruk, K.
Korzeniewski, M.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1193396.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anti-islanding protection
active frequency drift
grid converter
Opis:
Frequency based methods developed to detect an islanding condition in modern power grid structures have been discussed. The condition may occur in power grid lines to which additional energy sources with power electronic converters have been connected such as solar panels or wind turbines. It is a hazardous operating state for grid workers and devices connected to the islanded part of the grid. Such a state results from the inability to control amplitude and frequency of basic harmonic of the grid voltage. An islanding problem in a power grid with additional small energy sources has been discussed. A basic passive and active islanding detection method have been presented and compared with known frequency based algorithms, namely active frequency drift and active frequency drift with a positive feedback algorithm. Finally, a laboratory test of the proposed islanding detection methods in a three-phase grid with an AC-DC converter has been conducted. To demonstrate differences between the tested methods, total harmonic distortion injected into the output converter current and detection time of islanding state have been measured.
Źródło:
Power Electronics and Drives; 2017, 2, 37/1; 27-41
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific emitter identification using geometric features of frequency drift curve
Autorzy:
Zhao, Y.
Wui, L.
Zhang, J.
Li, Y.
Powiązania:
https://bibliotekanauki.pl/articles/200575.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
specific emitter identification
geometric features
frequency drift
adaptive fractional spectrogram
support vector machine
emiter
cechy geometryczne
dryf częstotliwości
spektrogram
Opis:
Specific emitter identification (SEI) is a technique for recognizing different emitters of the same type which have the same modulation parameters. Using only the classic modulation parameters for recognition, one cannot distinguish different emitters of a same type. To solve the problem, new features urgently need to be developed for recognition. This paper focuses on the common phenomenon of frequency drift, defines geometric features of frequency drift curve and, finally, proposes a practical algorithm of specific emitter identification using the geometric features. The proposed algorithm consists of three processes: instantaneous frequency estimation based on the adaptive fractional spectrogram, feature extraction of frequency drift curve based on geometric methods for describing a curve and recognition process based on support vector machine. Simulation results show that the identification rate is generally more than 98% above –5 dB of signal to noise ratio (SNR), and real data experiment verifies the practical performance of the proposed algorithm.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 1; 99-108
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method of frequency offset correction using coherent averaging
Autorzy:
Gajewski, P.
Łopatka, J.
Piotrkowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/308860.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
coherent averaging
jitter
drift
frequency offset correction
Opis:
This paper describes a new method of frequency offset correction to improve clock stability in communication systems where the temporary drift or jitter of phase angle is not accepted. This method bases on coherent spectral averaging with a special phase scanning algorithm. Achieved results show that proposed method is effective for strongly degraded signals. Method is useful for precise phase angle reconstruction in these systems where clock stability of the transceiver and receiver is insufficient.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 1; 142-146
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The “Mysterious” Kazlauskas: Exploring Lithuania’s Most Frequent Surname
Autorzy:
Walkowiak, Justyna B.
Powiązania:
https://bibliotekanauki.pl/articles/971883.pdf
Data publikacji:
2016-12-01
Wydawca:
Polska Akademia Nauk. Instytut Języka Polskiego PAN
Tematy:
surname frequency
Lithuanian surnames
surname loss
genetic drift
Opis:
The article presents the most frequent surname in Lithuania — Kazlauskas. Referring to the article “Mysterious Lewandowski” by K. Skowronek (2000), an attempt has been made to account for this frequency in three various ways. First, the principles behind the quantitative structure of anthroponomasticons (Zipf’s law) and the loss of surnames (genetic drift) are discussed. Then the Slavic origin of the surname under consideration has been highlighted as a typical trait of the majority of surnames in Lithuania. In connection with this fact, it has been stressed that caution must be exercised in proposing a thesis on its origin as a translation from Lithuanian on a mass scale, since this thesis requires plentiful empirical evidence. Finally, the etymology of the name is analyzed. Morphologically it is a typical surname derived from a toponym. This supposition is additionally supported by the existence in Poland of numerous localities called Kozłów, Kozłowo or similar name; these in turn are most likely to have been derived from appellative-based personal names of their owners or inhabitants, such as Kozieł.
Źródło:
Onomastica; 2016, 60; 175-186
0078-4648
Pojawia się w:
Onomastica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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