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Tytuł:
Photonic generation of broadly tunable radio-frequency signal using a reflective semiconductor optical amplifier
Autorzy:
Lu, Youxi
Wang, Fei
Gu, Jun
Shi, Lun
Peng, Mengmeng
Huang, Jingxin
Kang, Wen
Powiązania:
https://bibliotekanauki.pl/articles/173479.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
radio frequency signal generation
semiconductor optical amplifiers
four-wave mixing
Opis:
A novel scheme for photonic generation of broadly tunable radio frequency signal using a reflective semiconductor optical amplifier (RSOA) is demonstrated. A continuous wave emitted from the laser diode is modulated by a Mach–Zehnder modulator, then the modulated optical carrier is injected into the RSOA. Due to the four-wave mixing effect in the RSOA, the limited frequency components of the modulated signal are expanded, which directly lead to the generation of a wide frequency comb. Two optical tunable bandpass filters are parallelly connected to select the desired sidebands, which are launched into a photodetector or photomixer to generate radio frequency signal by beating. Using the proposed method, the bandwidth of generated radio frequency signal can range from 20 to 300 GHz.
Źródło:
Optica Applicata; 2019, 49, 1; 27-36
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-voltage overhead lines topology identification method based on high-frequency signal injection
Autorzy:
Ge, Haotian
Xu, Bingyin
Zhang, Xinhui
Bi, Yongjian
Powiązania:
https://bibliotekanauki.pl/articles/1955180.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high-frequency signal injection
low voltage overhead lines
topology identification
wtrysk sygnału wysokiej częstotliwości
linie napowietrzne niskiego napięcia
identyfikacja topologii
Opis:
The topology of low-voltage distribution systems changes with the load or the on/off position of the circuit switch. This will affect power flows, losses, and so on. This paper submits a new method to identify the topology of a low-voltage feeder using the injection high-frequency signal. An inductor can block the high-frequency signal. It can change the propagation direction of the injected high-frequency signal to make it propagate unidirectionally along the low-voltage feeder. By injecting a 5 MHz sinusoidal signal from the upstream direction of the low-voltage feeder, all the line segments and devices on the feeder can be identified. The wavelength of the high-frequency signal is short. The wavelength of the 5 MHz signal is 60 meters. Through the delay of different observation points on the feeder, the length of the line section can be roughly calculated. The high- frequency signal has an obvious reflection on the feeder. Using this feature, we can roughly calculate the length of the line segment. The correctness of the method is demonstrated by MATLAB simulation verification.
Źródło:
Archives of Electrical Engineering; 2021, 70, 4; 791-800
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple, fast and accurate four-point estimators of sinusoidal signal frequency
Autorzy:
Sienkowski, S.
Krajewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/221283.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sinusoidal signal
frequency estimation
frequency tracking
Opis:
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.
Źródło:
Metrology and Measurement Systems; 2018, 25, 2; 359-376
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impulse Noise Suppression Based on Power Iterative ICA in Power Line Communication
Autorzy:
Zhang, Wei
Luo, Zhongqiang
Xiong, Xingzhong
Powiązania:
https://bibliotekanauki.pl/articles/226439.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power line communication(PLC)
orthogonal frequency division multiplexing(OFDM) signal
independent component analysis(ICA)
impulse noise
Opis:
To overcome the detrimental influence of impulse noise in power line communication and the trap of scarce prior information in traditional noise suppression schemes , a power iteration based fast independent component analysis (PowerICA) based noise suppression scheme is designed in this paper. Firstly, the pseudo-observation signal is constructed by weighted processing so that single-channel blind separation model is transformed into the multi-channel observed model. Then the proposed blind separation algorithm is used to separate noise and source signals. Finally, the effectiveness of the proposed algorithm is verified by experiment simulation. Experiment results show that the proposed algorithm has better separation effect, more stable separation and less implementation time than that of FastICA algorithm, which also improves the real-time performance of communication signal processing.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 4; 651-656
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous Analysis of Vibrations and Noise in the Task of Minimizing Vibroacoustic Activity of Machines
Autorzy:
Dąbrowski, Z.
Dziurdź, J.
Powiązania:
https://bibliotekanauki.pl/articles/177692.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal separation
noise minimizing
frequency response function
Opis:
Simultaneous propagation of vibrations and noise has an important role in the task of minimizing vibroacoustic hazards on the station of operator of the construction machinery. In many cases vibrations transferred by the construction are processed to noise in different points of the machine. As a result, they may increase the level of noise at the workplace. The paper presents the proposition of a simple estimation of noise and vibration propagation paths of the machine. On the basis of the analysis of hydraulic excavator an effectiveness of a proposed procedure was shown. This procedure helps to minimize the transfer of vibrations of power unit in selected frequency ranges which led to the change of overall noise level in operator’s cab about 5 dB.
Źródło:
Archives of Acoustics; 2016, 41, 2; 303-308
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mobile Radio Beacons in Coastal Reserved Navigation System for Ships
Autorzy:
Kelner, J. M.
Ziółkowski, C.
Powiązania:
https://bibliotekanauki.pl/articles/1841623.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
radio beacons
coastal reserved navigation system
navigation system
signal Doppler frequency
Global Navigation Satellite System
Terrestrial Navigation System
Radio Navigation System
Opis:
At the turn of the 20th and 21st centuries, Global Navigation Satellite Systems (GNSSs) dominated navigation in air, sea, and land. Then, medium-range and long-range terrestrial navigation systems (TNSs) ceased to be developed. However, with the development of GNSS jamming and spoofing techniques, the TNSs are being re-developed, such as the Enhanced Loran. The Polish Ministry of Defense plans to develop and implement a medium-range backup navigation system for the Polish Navy which will operate in the Baltic coastal zone. This plan is a part of the global trend. This paper presents the concept of a reserve TNS (RNS) that is based on the signal Doppler frequency (SDF) location method. In 2016, the concept of the RNS, which is based on stationary radio beacons located on coastal lighthouses, has been presented. From the military viewpoint, the use of the mobile radio beacons, which may change their location, is more justified. Therefore, the paper presents an idea of using the mobile beacons for this purpose. In this paper, effectiveness of the mobile RNS is shown based on simulation studies.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2020, 14, 3; 603-610
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-efficiency carrier frequency estimation algorithm for real-time multi-domain communication signal analysis
Autorzy:
Wang, Q.
Yang, X.
Yan, X
Qin, K.
Powiązania:
https://bibliotekanauki.pl/articles/221239.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
carrier frequency estimation
multi-domain communication
signal analysis
Opis:
Based on real-time multi-domain communication signal analysis architecture, a high-efficiency blind carrier frequency estimation algorithm using the power spectrum symmetry of the measured modulated signal is presented. The proposed algorithm, which utilizes the moving averaged power spectrum achieved by the realtime spectrum analysis, iteratively identifies the carrier frequency in according to the power difference between the upper sideband and lower sideband, which is defined and revised by the estimated carrier frequency in each iteration. When the power difference of the two sidebands converges to the preset threshold, the carrier frequency can be obtained. For the modulation analysis, the measured signal can be coarsely compensated by the estimated result, and the residual carrier frequency error is eliminated by a following carrier synchronization loop. Compared with previous works, owing to the moving averaged power spectrum normalization and the smart iterative step variation mechanism for the two sidebands definition, the carrier frequency estimation accuracy and speed can be significantly improved without increasing the computational effort. Experimental results are included to demonstrate the outstanding performance of the proposed algorithm.
Źródło:
Metrology and Measurement Systems; 2014, 21, 2; 281-292
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single-tone frequency estimation based on reformed covariance for half-length autocorrelation
Autorzy:
Sienkowski, Sergiusz
Krajewski, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/220848.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
frequency estimator
sinusoidal signal
autocorrelation function
mean squared error
Opis:
This paper presents a new simple and accurate frequency estimator of a sinusoidal signal based on the signal autocorrelation function (ACF). Such an estimator was termed as the reformed covariance for half-length autocorrelation (RC-HLA). The designed estimator was compared with frequency estimators well-known from the literature, such as the modified covariance for half-length autocorrelation (MC-HLA), reformed Pisarenko harmonic decomposition for half-length autocorrelation (RPHD-HLA), modified Pisarenko harmonic decomposition for half-length autocorrelation (MPHD-HLA), zero-crossing (ZC), and iterative interpolated DFT (IpDFT-IR) estimators. We determined the samples of the ACF of a sinusoidal signal disturbed by Gaussian noise (simulations studies) and the samples of the ACF of a sinusoidal voltage (experimental studies), calculated estimators based on the obtained samples, and computed the mean squared error (MSE) to compare the estimators. The errors were juxtaposed with the Cramér-Rao lower bound (CRLB). The research results have shown that the proposed estimator is one of the most accurate, especially for SNR>25dB. Then the RC-HLA estimator errors are comparable to the MPHD-HLA estimator errors. However, the biggest advantage of the developed estimator is the ability to quickly and accurately determine the frequency based on samples collected from no more than five signal periods. In this case, the RC-HLA estimator is the most accurate of the estimators tested.
Źródło:
Metrology and Measurement Systems; 2020, 27, 3; 473-493
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of signal of X4 unmanned aerial vehicle
Autorzy:
Mięsikowska, M.
Nowakowski, M.
Lorenc, W.
Chodnicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/244241.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
unmanned aerial vehicles
drones
time-dependent frequency analysis
signal analysis
Opis:
Unmanned aerial vehicles are increasingly used in military service and in everyday life. Drones can be used for many purposes i.e. recreation, military applications or to increase the safety of citizens. Unmanned aerial vehicle can become a source of information, based on which object/operator can make a certain decisions. Unmanned aerial vehicles are increasingly used in ecological research. UAV can be capable of making sophisticated maps and may scan terrain for forest fires. They can contribute to safe infrastructure maintenance and management. Often, however, these objects being in the possession of civilians can become a source of danger and impact on privacy. It is therefore necessary to detect and recognize such objects in a real time. The aim of this study was to analyse the acoustic signal of unmanned aerial vehicle equipped with four rotating propellers – X4 structure (12000 rpm/min). The maximum speed of the object is 60 km/h and the ceiling to which it can operate flights reaches 1500 m AGL. The acoustic signal was acquired by Olympus LS11 digital recorder. Recordings were performed when the object is away from the recording equipment at the distance of 1 km. Analysis of the recorded signal can provide a significant information about the unmanned aerial vehicle. Results showed that some specific characteristic signal features are clearly visible in the signal even if the object is far away from the recording equipment.
Źródło:
Journal of KONES; 2016, 23, 3; 321-326
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of the Fundamental Frequency of the Speech Signal Compressed by MP3 Algorithm
Autorzy:
Milivojević, Z. N.
Brodić, D.
Powiązania:
https://bibliotekanauki.pl/articles/177285.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fundamental frequency
speech compression
speech processing
signal representation
MP3
Opis:
The paper analyzes the estimation of the fundamental frequency from the real speech signal which is obtained by recording the speaker in the real acoustic environment modeled by the MP3 method. The estimation was performed by the Picking-Peaks algorithm with implemented parametric cubic convolution (PCC) interpolation. The efficiency of PCC was tested for Catmull-Rom, Greville, and Greville two- parametric kernel. Depending on MSE, a window that gives optimal results was chosen.
Źródło:
Archives of Acoustics; 2013, 38, 3; 363-373
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection and diagnosis of bearing defects using vibration signal processing
Autorzy:
Bouaouiche, Karim
Menasria, Yamina
Khalfa, Dalila
Powiązania:
https://bibliotekanauki.pl/articles/27309892.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
vibration signal
bearing
signal processing
envelope spectrum
fault frequency
sygnał wibracyjny
łożysko
przetwarzanie sygnałów
częstotliwość usterek
Opis:
This work presents an analysis of vibration signals for bearing defects using a proposed approach that includes several methods of signal processing. The goal of the approach is to efficiently divide the signal into two distinct components: a meticulously organized segment that contains relatively straightforward information, and an inherently disorganized segment that contains a wealth of intricately complex data. The separation of the two component is achieved by utilizing the weighted entropy index (WEI) and the SVMD algorithm. Information about the defects was extracted from the envelope spectrum of the ordered and disordered parts of the vibration signal. Upon applying the proposed approach to the bearing fault signals available in the Paderborn university database, a high amplitude peak can be observed in the outer ring fault frequency (45.9 Hz). Likewise, for the signals available in XJTU-SY, a peak is observed at the fault frequency (108.6 Hz).
Źródło:
Archive of Mechanical Engineering; 2023, LXX, 3; 433--452
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Speech Emotion Recognition Based on Voice Fundamental Frequency
Autorzy:
Dimitrova-Grekow, Teodora
Klis, Aneta
Igras-Cybulska, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/177227.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
emotion recognition
speech signal analysis
voice analysis
fundamental frequency
speech corpora
Opis:
The human voice is one of the basic means of communication, thanks to which one also can easily convey the emotional state. This paper presents experiments on emotion recognition in human speech based on the fundamental frequency. AGH Emotional Speech Corpus was used. This database consists of audio samples of seven emotions acted by 12 different speakers (6 female and 6 male). We explored phrases of all the emotions – all together and in various combinations. Fast Fourier Transformation and magnitude spectrum analysis were applied to extract the fundamental tone out of the speech audio samples. After extraction of several statistical features of the fundamental frequency, we studied if they carry information on the emotional state of the speaker applying different AI methods. Analysis of the outcome data was conducted with classifiers: K-Nearest Neighbours with local induction, Random Forest, Bagging, JRip, and Random Subspace Method from algorithms collection for data mining WEKA. The results prove that the fundamental frequency is a prospective choice for further experiments.
Źródło:
Archives of Acoustics; 2019, 44, 2; 277-286
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of vibroacoustic signal to diagnose disck braking system
Autorzy:
Sawczuk, W.
Powiązania:
https://bibliotekanauki.pl/articles/244459.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
disc brake
wear of friction pad
vibration signal
amplitude characteristics
frequency characteristics
Opis:
Attempt to raise train speed involves application of greater braking power i.e. braking systems rapidly absorbing and dispersing stored heat energy. To maintain high efficiency of braking system in the whole operational process, it is necessary to control the friction set: brake and pad before reaching limitary wear particularly of friction pads. Stable and constant - in the whole speed range- coefficient of friction "mi" and realization of greater pad's pressures to the disc because of better conditions of warmth offtaking generated during braking into the athmoshere are basic advantages of disc brake systems [8]. Few disadvantages of disc brake include a lack of possibility of controlling the condition of the friction set: brake and pad in the whole operation time. It is particularly observable in rail cars, where disc brakes are mounted on the axle of the axle set between the wheels. To check the wear of friction pads and brake discs it is necessary to apply inspection channel to carry out inspections, and to carry out replacement of friction parts in case they reach their limitary wear. The purpose of this research is to apply vibration signal of pad calipers to assess the wear of friction pads of disc brake by defining characteristics of time, amplitude and selected frequency characteristics during tests at internal brake station.
Źródło:
Journal of KONES; 2011, 18, 1; 525-534
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of features for the automatic recognition of OFDM signals in monitoring or cognitive receivers
Autorzy:
Liedtke, F.
Albers, U.
Powiązania:
https://bibliotekanauki.pl/articles/308231.pdf
Data publikacji:
2008
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
OFDM signal recognition
discrimination features
cepstrum evaluation
estimation of frequency channel number
Opis:
The automatic recognition of signal types is an important task of monitoring receivers and also cognitive receivers. Several modulation recognition or classification procedures exist for single channel signal types while a simple robust procedure for automatic recognition of OFDM signals is lacking because of its numerous frequency channelslying close together. The task considered in this paper is the discrimination between OFDM (or multi-channel) signals and other signal types. The number of frequency channels of the OFDM signals is assumed to be unknown a priori. So, together with the automatic OFDM detection the estimation of the number of frequency channels is treated. Several discrimination features have been examined and the most promising ones are described: measures of the variation, of the skewness, of the kurtosis, and of the specific picket-fence shape of the spectrum which is typical for many OFDM signals. For a number of real-world OFDM samples, recorded from the high frequency range, results are presented. An automatic discrimination from single channel or noise like signals is achieved and the number of system channels can be estimated.
Źródło:
Journal of Telecommunications and Information Technology; 2008, 2; 30-36
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time–frequency Analysis of the EMG Digital Signals
Autorzy:
Kuniszyk-Jóźkowiak, W.
Jaszczuk, J.
Sacewicz, T.
Codello, I.
Powiązania:
https://bibliotekanauki.pl/articles/106250.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
time-frequency analysis
EMG signal
Fast Fourier Transform
predictive analytics
wavelet analysis
Opis:
In the article comparison of time-frequency spectra of EMG signals obtained by the following methods: Fast Fourier Transform, predictive analysis and wavelet analysis is presented. The EMG spectra of biceps and triceps while an adult man was flexing his arm were analysed. The advantages of the predictive analysis were shown as far as averaging of the spectra and determining the main maxima are concerned. The Continuous Wavelet Transform method was applied, which allows for the proper distribution of the scales, aiming at an accurate analysis and localisation of frequency maxima as well as the identification of impulses which are characteristic of such signals (bursts) in the scale of time. The modified Morlet wavelet was suggested as the mother wavelet. The wavelet analysis allows for the examination of the changes in the frequency spectrum in particular stages of the muscle contraction. Predictive analysis may also be very useful while smoothing and averaging the EMG signal spectrum in time.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2012, 12, 2; 20-25
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 42

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