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PL
W artykule przedstawiono nowe czasowo-dyskretne algorytmy czteropunktowe umożliwiające śledzenie częstotliwości sygnału sinusoidalnego. Opracowane algorytmy porównano z czasowo-dyskretnym algorytmem trzypunktowym zaproponowanym przez Vizireanu. W celu porównania algorytmów wykonano symulacje polegające na śledzeniu częstotliwości sygnału sinusoidalnego zakłóconego szumem Gaussa. Pokazano, że opracowane algorytmy umożliwiają śledzenie częstotliwości z większą dokładnością.
EN
The article presents new discrete-time four-point algorithms that enable tracking the sinusoidal signal frequency. The developed algorithms have been compared with the discrete-time three-point algorithm proposed by Vizireanu. In order to compare the algorithms, simulations have been performed, consisting in tracking the sinusoidal signal frequency disturbed by Gaussian noise. It has been shown that the developed algorithms allow frequency tracking with greater accuracy.
EN
In this paper, two new sinusoidal signal frequency estimators calculated on the basis of four equally spaced signal samples are presented. These estimators are called four-point estimators. Simulation and experimental research consisting in signal frequency estimation using the invented estimators have been carried out. Simulation has also been performed for frequency tracking. The simulation research was carried out applying the MathCAD computer program that determined samples of a sinusoidal signal disturbed by Gaussian noise. In the experimental research, sinusoidal signal samples were obtained by means of a National Instruments PCI-6024E data acquisition card and an Agilent 33220A function generator. On the basis of the collected samples, the values of four-point estimators invented by the authors and, for comparison, the values of three- and four-point estimators proposed by Vizireanu were determined. Next, estimation errors of the signal frequency were determined. It has been shown that the invented estimators can estimate a signal frequency with greater accuracy.
EN
To maintain power system operation in a balanced and stable condition, the frequency deviation and the rate of frequency change information are highly desired in monitoring and protection applications of the power grid. How to obtain frequency information more accurately and efficiently has been the topic discussion for decades. PMUs (Phaser Measurement Unit) are the most widely-used devices for measuring phase angle differences and they also provide very accurate frequency information. However, the high installation cost of PMUs limits their applications for wide area control and stability analysis of power system. Thanks to commercial GPS receivers and the fast developments in Ethernet networks, an affordable wide area, quasi real-time, GPS synchronized frequency measurement is now possible. This paper introduces a portable networked Frequency Disturbance Recorder (FDR) device, which can be used at any 110V wall outlet and transmit measured frequency data remotely via the Ethernet. The practical issues and challenges of the device design and implementation are analyzed and discussed. Based on these low cost FDRs, a US-wide Frequency Network (FNET) has been implemented at Virginia Tech and some power system monitoring applications are being developed by taking fully advantage of the FDRs.
4
Content available remote A robust pilot based frequency tracking method for DRM receivers
EN
A novel implementation of a frequency tracking method for DRM receivers is presented that provides an extended tracking range of about 100% of the subcarrier spacing. The approach is based on a frequency control loop augmented by a noise and jitter suppressing feedforward path. Simulation results for an AWGN channel demonstrate the robustness of the proposed method. The paper gives also an overview concerning the DRM system in general. In addition, aspects of a possible receiver structure are considered.
PL
Zaprezentowano nowoczesną implementację metody śledzenia częstotliwości dla odbiorników DRM, która umożliwia rozszerzone śledzenie w zakresie 100% przestrzeni podnośniej. Rozwiązanie zostało oparte na pętli częstotliwościowej wzmocnionej przez usuwanie szumu i drgań sprzężeniem do przodu. Wyniki symulacji kanału AWGN dowodzą wydajności proponowanej metody. W artykule zamieszczono również ogólny przegląd systemów DRM. Dodatkowo zostały rozważone aspekty możliwej struktury odbiornika.
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