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Tytuł:
Resource allocation in MIMO systems specific to radio communication
Autorzy:
Ghaderi, Bahar
Parhizgar, Naser
Powiązania:
https://bibliotekanauki.pl/articles/140794.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spatial modulation
multi quadrature amplitude modulation
modulation
Huffman coding
MIMO systems
Opis:
The performance of the multi-input multi-output (MIMO) systems can be improved by spatial modulation. By using spatial modulation, the transmitter can select the best transmit antenna based on the channel variations using channel state information (CSI). Also, the modulation helps the transmitter to select the best modulation level such that the system has the best performance in all situations. Hence, in this paper, two issues are considered including spatial modulation and information modulation selection. For the spatial modulation, an optimal solution for obtaining the probability of selecting antenna is calculated and then Huffman coding is used such that the transmitter can select the best transmit antenna to maximize the channel capacity. For the information modulation, a multi quadrature amplitude modulation (MQAM) strategy is used. In this modulation, the modulation size is changed based on the channel state variations; therefore, the best modulation index is used for transmitting data in all channel situations. In simulation results, the optimal method is compared with Huffman mapping. In addition, the effect of modulation on channel capacity and a bit error rate (BER) is shown.
Źródło:
Archives of Electrical Engineering; 2019, 68, 1; 91-100
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analog-based duobinary-4-PAM for electrical bandwidth limited optical fiber links
Autorzy:
Suhr, L.F.
Madsen, P.
Monroy, I. T.
Olmos, J. J. V.
Powiązania:
https://bibliotekanauki.pl/articles/173933.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical communications
advanced modulation formats
multilevel modulation
Opis:
This paper presents a demonstration of a seven level duobinary-4-PAM signal operating at 10.16 Gbit/s. The polybinary generation is achieved by a simple electrical Bessel filter of 5th order, with a frequency cut-off of 1.8 GHz. We assess the impact of the filter placement, either at the transmitter or the receiver, and find the impact is minimal in terms of bit error rate performance in transmissions of up to 40 km of single mode fiber.
Źródło:
Optica Applicata; 2016, 46, 1; 71-78
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binaural masking of amplitude modulation
Autorzy:
Kordus, M.
Sęk, A.
Kociński, J.
Powiązania:
https://bibliotekanauki.pl/articles/177557.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
masking
masking in the modulation domain
modulation filterbank
Opis:
A new concept concerned with the transformation of acoustic stimuli in the auditory system postulates the existence of a form of spectral analysis applied to the amplitude changes of the stimuli. It is assumed that this analysis takes place in the so-called modulation filters, i.e. bandpass linear filters tuned to different rates of the amplitude changes. The most striking argument supporting this idea is an effect of masking in the amplitude modulation domain whose nature can be easily explained basing on this concept. As the modulation filters are situated on the higher levels of the auditory system, it is also assumed that this form of masking is entirely a central process. However, most of the studies concerned with masking in the modulation domain used monaural listening only. Therefore, the main purpose of the presented here experiments was to investigate whether this type of masking is entirely a central process. Using a Three-Alternative Forced-Choice (3AFC) procedure the binaural and monaural masked thresholds of amplitude modulation were determined. A sinusoidal carrier at a frequency of 4 kHz was amplitude modulated by a specially designed band of noise characterized by a very low value of the crest factor, which was used as a masking signals. Different bandwidths of the modulating masking signals were used as well as different center frequencies to investigate whether the masking patterns in the modulation domain depend on the masker bandwidth and its center frequency. The modulating target (masked) signal was a pure tone at a frequency range from 2 to 256 Hz. Both modulating signals were applied to the same sinusoidal carrier signal. The most effective masking was noticed when the rate of the sinusoidal modulation was close to the center frequency of the masking signal or when it was in its spectral range and decreased outside of this range. The character of this dependence confirms the existence of some form of a frequency selectivity in the modulation rate domain similarly to the audible frequency domain. The thresholds for monaural and binaural listening were very close to each other. This implies that masking in the modulation domain is a central process.
Źródło:
Archives of Acoustics; 2005, 30, 1; 5-17
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive procedure for automatic modulation recognition
Autorzy:
Liedtke, F.
Powiązania:
https://bibliotekanauki.pl/articles/308334.pdf
Data publikacji:
2004
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
modulation recognition
modulation classification
signal analysis
radio monitoring
Opis:
An adaptive procedure for automatic modulation recognition is described. With it the automatic modulation classification and recognition of radio communication signals with a priori unknown parameters is possible effectively. The results of modulation recognition are important in the context of radio monitoring or electronic support measurements. The special features of the procedure are the possibility to adapt it dynamically to nearly all modulation types, and the capability to recognize continuous phase modulation (CPM) signals like Gaussian minimum-shift keying (GMSK) too. A time synchronization to the symbol rate is not necessary.
Źródło:
Journal of Telecommunications and Information Technology; 2004, 4; 91-97
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Models for Distribution of the Envelope and Phase of Linearly Modulated Signals in AWGN Channel
Autorzy:
Moazzeni, T
Jiang, Y.
Selvaraj, H.
Chen, T.
Powiązania:
https://bibliotekanauki.pl/articles/226459.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital modulation
linear modulation
probability density function
phase
AWGN
Opis:
In this paper, analytical expressions for the distribution of the envelope and phase of linearly modulated signals such as BPSK, M-PSK, and M-QAM in AWGN are presented. We perform numerical simulations for different orders of signal constellations. The results show that the proposed theoretical models are in excellent agreement with the estimated distributions from various numerical experiments.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 1; 79-82
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission Perspective on the Mechanism of Coarse and Fine Crackle Sounds
Autorzy:
Lu, Bing-Yuh
Hsueh, Meng-Lun
Wu, Huey-Dong
Powiązania:
https://bibliotekanauki.pl/articles/1953484.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
crackles
computer simulation
lung sound
respiration
amplitude modulation
frequency modulation
Opis:
The possibility of a normal distribution indicates that few particles are in the same phase during a breath and their reflections can be observed on the chest wall, then a few explosive waves with relatively large power occurr occasionally. Therefore, the one-cycle sine wave which is simulated as a single burst of the explosive effect phenomenon penetrates through the chest wall and was analysed to explore the reason of the crackle sounds. The results explain the differences between the definitions of crackle proposed by Sovijärvi et al. (2000a). The crackles in the lungs were synthesised by a computer simulation. When the coarse crackles occur, the results indicate that higher burst frequency carriers (greater than 100 Hz) directly penetrate the bandpass filter to simulate the chest wall. The simulated coarse crackle sounds were low pitched, with a high amplitude and long duration. The total duration was greater than 10 ms. However, for a lower frequency carrier (approximately 50 Hz), the fundamental frequency component was filtered out. Therefore, the second harmonic component of the lower frequency carrier, i.e., the fine crackle, penetrated the chest wall. Consequently, it is very possible that the normal lung sounds may contain many crackle-shaped waves with very small amplitudes because of the filtering effects of the chest wall, environment noises, electric devices, stethoscopes, and human ears, the small crackles disappear in the auscultations. In addition, our study pointed out that some unknown crackles of the very low frequency under the bandwidth of the human ears cannot penetrate the airways and be detected by medical doctors. Therefore, it might be necessary to focus advanced electronic instrumentation on them in order to analyse their possible characteristics for diagnosis and treatment of the respiration system.
Źródło:
Archives of Acoustics; 2021, 46, 2; 289-300
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pilot Based MMSE Channel Estimation for Spatial Modulated OFDM Systems
Autorzy:
Soman, Anetha Mary
Nakkeeran, R.
Shinu, Mathew John
Powiązania:
https://bibliotekanauki.pl/articles/2055222.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MIMO
multicarrier modulation
spatial modulation
channel estimation
channel model
interpolation
Opis:
Due to the multifold growth in demands of multimedia services and mobile data, the request for increased channel capacity in mobile and wireless communication has been quickly increasing. Developing a wireless system with more spectral efficiency under varying channel condition is a key challenge to provide more bit rates with limited spectrum. Multiple Input Multiple Output(MIMO) system with Orthogonal Frequency Division Multiplexing (OFDM) gives higher gain by using the direct and the reflected signals, thus facilitating the transmission at high data rate. An integration of Spatial Modulation (SM) with OFDM (SM OFDM) is a newly evolved transmission technique and has been suggested as a replacement for MIMO -OFDM transmission. In practical scenarios, channel estimation is significant for detecting transmitted data coherently. This paper proposes pilot based, Minimum Mean Square Error (MMSE) channel estimation for the SM OFDM communication system. We have focused on analyzing Symbol Error Rate (SER) and Mean Square error (MSE) under Rayleigh channel employing International Telecommunication Union (ITU) specified Vehicular model of Pilot based MMSE channel estimator using windowed Discrete Fourier Transform (DFT) and MMSE weighting function. Simulation output shows that proposed estimator’s SER performance lies close to that of the MMSE optimal estimator in minimizing aliasing error and suppressing channel noise by using frequency domain data windowing and time domain weighting function. Usage of the Hanning window eliminates error floor and has a compact side lobe level compared to Hamming window and Rectangular window. Hanning window has a larger MSE at low Signal to Noise Ratio (SNR) values and decreases with high SNR values. It is concluded that data windowing technique can minimize the side lobe level and accordingly minimize channel estimation error when interpolation is done. MMSE weighting suppresses channel noise and improves estimation performance. Since Inverse Discrete Fourier Transform(IDFT)/DFT transforms can be implemented with fast algorithms Inverse Fast Fourier Transform( IFFT)/Fast Fourier Transform(FFT) computational complexity can be remarkably reduced.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 4; 685--691
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Digital vector modulator with diagnostic circuit for particle accelerator
Autorzy:
Tarnowski, S.
Piotrowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/397924.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
modulacja wektorowa
modulacja cyfrowa
diagnostyka
vector modulation
digital modulation
diagnostics
Opis:
Modern particle accelerators[8] have very strict requirements for controlling signal. To generate signal controlling field in cavities there is a possibility to use digital vector modulator and analog upconverter[6]. Hardware circuit consists of FPGA device, digital to analog converter and low pass filter. For experiments there is also a need to design and develop measurement circuit. Same circuit could be used in final application as diagnostics module. This enables an option for constant long term measurement and fault detection. This paper presents construction of such module.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 1; 85-88
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental research of the AMWG algorithm for assessing amplitude modulation in wind turbine noise
Autorzy:
Czapla, Marcjanna
Wszołek, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/24202008.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
wind turbine noise
amplitude modulation
modulation depth
modulation frequency
hałas turbin wiatrowych
modulacja amplitudy
głębokość modulacji
częstotliwość modulacji
Opis:
The operation of a wind turbine (WT) is characterized by fluctuations in sound pressure amplitude associated with the passage of the propeller blade through the tower. Amplitude Modulation (AM) is one of the factors that contributes to the increased annoyance of wind turbine noise. The phenomenon of AM is currently the subject of research in many research centers around the world in the context of a parametric assessment of its impact on annoyance. Despite the development of many methods to measure the AM of a WT noise, there is no commonly accepted method. This paper discusses the most crucial factors that stimulate the phenomenon of AM and the implementation in the MATLAB environment of the algorithm to find the frequency and depth of AM proposed by the Amplitude Modulation Working Group (AMWG). The results of verification of the developed algorithm as well as the measurement results of the frequency and depth of modulation for two measurement samples of a 2 MW wind turbine are presented.
Źródło:
Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022317
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The diagnosis of onboard generators (alternators)
Autorzy:
Gębura, A.
Radoń, T.
Powiązania:
https://bibliotekanauki.pl/articles/258804.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
technical diagnostics
frequency modulation
Opis:
In the paper selected problems related to diagnostics of onboard generators and alternators fitted with control systems are discussed. Problems refer to commutator generators and synchronous single- and threephase alternators. Special attention is paid to commutation effects. Results of incorrectness and possibility to detect them are discussed. There are also discussed effects associated with changes in a character of pulsation, which occur during shortings or insulation clearances in rotor or stator wiring. Possibility of diagnosis of generator’s or alternator’s parts by means of analysis of pulsation component parameters is indicated. In the case of alternators a number of diagnostic methods based on observation of changes in shape of voltage or frequency modulation, is discussed. This allows to detect many mechanical or electrical faults of generators, alternators or their control systems.
Źródło:
Polish Maritime Research; 2009, 3; 36-40
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recognition of narrowband radio signals using autoregressive models and pattern comparison approach
Autorzy:
Łopatka, J.
Powiązania:
https://bibliotekanauki.pl/articles/308156.pdf
Data publikacji:
2002
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
signal models
modulation recognition
Opis:
This paper presents an improved spectral recognition method for digitally modulated radio signals. It is based on a signal autoregressive (AR) model. Model poles are used as signal features for neural network based on recognition process. To reduce an influence of the signal noise and distortions introduced by the digital receiver, a nonlinear Z plane transformation is proposed.
Źródło:
Journal of Telecommunications and Information Technology; 2002, 1; 56-59
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy logic classifier for radio signals recognition
Autorzy:
Łopatka, J.
Pędzisz, M.
Powiązania:
https://bibliotekanauki.pl/articles/308362.pdf
Data publikacji:
2001
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
modulation recognition
fuzzy logic
Opis:
This paper presents a new digital modulation recognition algorithm for classifying baseband signals in the presence of additive white Gaussian noise. Elaborated classification technique uses various statistical moments of the signal amplitude, phase and frequency applied to the fuzzy classifier. Classification results are given and it is found that the technique performs well at low SNR. The benefits of this technique are that it is simple to implement, has generalization property and requires no apriori knowledge of the SNR, carrier phase or baud rate of the signal for classification.
Źródło:
Journal of Telecommunications and Information Technology; 2001, 2; 31-34
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mодуляция как переводческая трансформация
Modulation as a translation transformation
Autorzy:
Гочев (Gochev), Гочо (Gocho)
Powiązania:
https://bibliotekanauki.pl/articles/967812.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
translation
modulation
translation transformation
Opis:
Modulation is a process which involves changing the informative parameters of the source language word. The concrete manifestation of this transformation is the act of replacing the source language words with equivalents unrelated to the systematic regularities of lexis and as such they might a) have relevance to these regularities, i.e. the equivalent exhibits a semantic or associative link with the source language word, or b) not have relevance to these regularities, i.e. the equivalent does not exhibit a semantic or associative link with the source language word, but its use is justified by extralinguistic factors (e.g. logical reasoning or a concrete situation).
Źródło:
Acta Universitatis Lodziensis. Folia Linguistica Rossica; 2012, 08; 43-49
1731-8025
2353-9623
Pojawia się w:
Acta Universitatis Lodziensis. Folia Linguistica Rossica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Symulacyjna aproksymacja charakterystyki przetwarzania flickermetru dla modulacji amplitudy i częstotliwości
Simulation approximation of flickermeter conversion characteristic for amplitude and frequency modulation
Autorzy:
Majchrzak, J.
Wiczyński, G.
Powiązania:
https://bibliotekanauki.pl/articles/156720.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
flikermetr
wskaźnik Pst
modulacja AM
modulacja FM
flickermeter
Pst indicator
FM modulation
AM modulation
Opis:
Flickermetr jest potoczną nazwą układu pomiarowego przeznaczonego do oceny odczuwania migotania światła wywołanego wahaniami napięcia. Normatywna charakterystyka przetwarzania flickermetru jest określona mało licznym zestawem par wartości głębokości modulacji i częstotliwości harmonicznego lub prostokątnego sygnału modulującego dla modulacji amplitudy napięcia wejściowego. Wielkością wyjściową jest wskaźnik krótkookresowego migotania światła Pst. W celu dokładniejszego odtworzenia charakterystyki przeprowadzono badania symulacyjne dla modulacji amplitudy i częstotliwości napięcia wejściowego. Zamodelowano elementy toru normatywnego flickermetru, tj. filtry o stałych parametrach zapisane w postaci operatorowej wraz z multiplikatorami, narzędzie do wyznaczania wartości Pst, źródło sygnału testowego oraz narzędzia do prezentacji i archiwizacji wyników badań. W artykule przedstawiono wyniki badań symulacyjnych zrealizowanych przy pomocy standardowych przebiegów testowych dla modulacji amplitudy AM oraz częstotliwości FM. Zamieszczono specyficzne fragmenty wyznaczonych charakterystyk oraz przykład wpływu ograniczenia pasma napięcia wejściowego na wynik pomiaru flickermetrem dla modulacji FM. Wyniki symulacji porównano z nielicznymi punktami normatywnymi. Sformułowano uwagi przydatne w diagnostyce flickermetru.
Flickermeter is a measurement system for estimation of the disturbances coming from flickering of light caused by the fluctuations of voltage. The disturbances are described on the basis of values of short-term coefficient Pst and long-term coefficient Plt of light flickers. The flickermeter system considered in the paper consists of two main components: a signal channel simulating perception processes in the chain: light source-eye-brain and a statistics module. Signal chains action is a map for bounded number of standard points of characteristic conversion. The simulation works with realization interpolation and extrapolation standard points was advisable. Presented results come from tests for AM and FM modulation.Before using the results, the verification was necessary. The conclusions formulated are useful in flickermeter's diagnostic.
Źródło:
Pomiary Automatyka Kontrola; 2007, R. 53, nr 9 bis, 9 bis; 629-632
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaotic-based Orthogonal Frequency Division Multiplexing with Index Modulation
Autorzy:
Hussien, Sura H.
Abdullah, Hamsa A.
Powiązania:
https://bibliotekanauki.pl/articles/2174449.pdf
Data publikacji:
2022
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
AWGN
chaos communications
DCSK
index modulation
Opis:
Orthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of the available transmit entities. Thanks to such an approach, it offers a novel method for the transmission of extra data bits. Recent years have seen a great interest in chaos-based communications. The spectrum-spreading signals used in chaotic signal modulation technologies are orthogonal to the existing mixed signals. This paper presents how well a non-coherent differential chaos shift keying communication system performs across an AWGN. Different types of detection methods are simulated, bit error rate and power spectral density are calculated and then compared with standard OFDM with index modulation. The results of simulations concerning the performance of a DCSK system, adding to the security of the proposed solution and offering a comparable bit error rate performance, are presented in the paper as well.
Źródło:
Journal of Telecommunications and Information Technology; 2022, 4; 33--38
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modified Topology and Modulation Technique for Z-Source Neutral-Point Clamped Inverter
Autorzy:
Akbari, Ehsan
Zishan, Farhad
Powiązania:
https://bibliotekanauki.pl/articles/2175930.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
modulation
optimization
multilevel inverter
MZS-NPC
Opis:
The impedance network makes it possible to increase and decrease the voltage, which is not available in normal inverters (voltage and current sources).This paper presents a modified topology and modulation technique for a three-phase Modified Z-Source Neutral-Point Clamped (MZS-NPC) inverter. A modulation scheme for the proposed topology is designed based on maximum gain control method to achieve the maximum voltage gain by simple implementation and balancing the neutral point voltage of the dc link. In order to supply the desired voltage to the critical load in an islanded micro-grid, a closed-loop ac voltage controller is realized in fuel cell or photovoltaic applications based on the proposed inverter. The ability to reinforce and validity of topology operations and modulation techniques has been demonstrated by simulation. It should be noted that the simulations are implemented in MATLAB / Simulink software.
Źródło:
Power Electronics and Drives; 2022, 7, 42; 210--226
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proposed Methodology for the Annoyance Penalty of Amplitude Modulated Wind Turbine Noise
Autorzy:
Makarewicz, Rufin
Powiązania:
https://bibliotekanauki.pl/articles/2141682.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
annoyance
wind turbine noise
amplitude modulation.
Opis:
Amplitude modulation increases the annoyance caused by wind turbine noise. One gets the improved annoyance when a penalty is added to the measured or calculated time-average sound level. The amplitude modulated wind turbine noise consists of pulses. Each of them could be characterized by the short time-average sound level and the modulation depth. The latter determines the pulse penalty. This paper shows how to calculate the improved annoyance of amplitude modulated wind turbine noise, when the short time-average sound level and the penalty for each pulse are known. A special case of identical pulses is discussed. The proposed methodology needs to be tested by research.
Źródło:
Archives of Acoustics; 2022, 47, 1; 125-128
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PLD we wspomaganiu demodulacji drgań maszyn
PLD aided demodulation of machine vibrations
Autorzy:
Krzyworzeka, P.
Cioch, W.
Powiązania:
https://bibliotekanauki.pl/articles/327694.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
diagnostyka
modulacja
synchronizm
diagnostic
modulation
synchronism
Opis:
W diagnozowaniu maszyn, dla których realizacja celu podstawowego obejmuje powtarzanie sekwencji zdarzeń podobnych, można wykorzystać PLD dla wspomagania demodulacji sygnału drganiowego w niestacjonarnych stanach pracy maszyny. Zastosowana transformacja skali czasu powoduje wyrównanie długości dyskretnej reprezentacji kolejnych cykli i zbliża rezultat do sygnału stacjonarnego zachowując modulacje AM i PM. Nawet zastosowanie demodulatorów asynchronicznych prowadzi wówczas do wyraźnego zmniejszenia uchybu obciążenia rezultatu. zmniejszenia obciążeń wyników. Przedstawiono rezultaty badań dla sygnałów modelowych i rzeczywistych.
This paper is concerned with the PLD (Procedure of Linear Decimation) aided output biasing elimination which takes into account some particularities of rotating machinery signal modulation. Rotating speed fluctuations or trend affect demodulation procedure due to nonlinear trend of carrier frequency. The proposed time scale transformation, denoted as PLD, aims to reduce demodulation error by employing linear approximation of carrier cycle short-term changes. Some examples of simulated and real signal asynchronous demodulations are also discussed hereby.
Źródło:
Diagnostyka; 2006, 2(38); 199-210
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decreasing of error probability in telecommunication access networks by using amplitude modulation of many components
Autorzy:
Klymash, M.
Gorbatyy, I.
Powiązania:
https://bibliotekanauki.pl/articles/411412.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
telecommunication access network
data transmission
bit error rate
quadrature amplitude modulation
amplitude modulation of many components
Opis:
The paper addresses the research of data transmission technologies in telecommunication access networks. These networks are characterized by limited bandwidth and are suitable for high speed data transmission. Particular attention is paid on the data transmission technologies in telecommunication access networks based on symmetrical telecommunication lines. Paper proposes the method of adaptive data transmission in telecommunication access networks using amplitude modulation of many components. The results of mathematical modeling are presented, which allows estimating the bit error rate decrease in telecommunication access networks using this method.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2014, 3, 1; 55-60
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of space vector modulation algorithm on characteristics of three-phase voltage inverter for drives of optical telescopes
Autorzy:
Tomasov, V.
Usoltsev, A.
Zolov, P.
Gribanov, P.
Powiązania:
https://bibliotekanauki.pl/articles/200303.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multilevel inverter
space vector modulation
modulation algorithm
current ripple
precision AC drive
inwerter
modulacja
napęd AC
Opis:
The effect of space vector modulation algorithm on magnitude of current vector ripples was considered on the mathematical model of a three-level three-phase voltage inverter with symmetric active inductive load. Limitations on the use of such inverters as a power supply for precision drive of optical telescopes were specified.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 5; 629-637
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modulation of Doxorubicin Cytotoxicity by Isoliquiritin and Cynarin Combination on Different Cancer Cell Lines
Autorzy:
Al-AdamI, Salat G.
Al-Khateeb, EKBAL H.
NUMAN, NAWFAL A.
ABBAS, Mannal M.
Tawfiq, FATIMA A.
Shakya, Ashok K.
Powiązania:
https://bibliotekanauki.pl/articles/895633.pdf
Data publikacji:
2020-06-29
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
cytotoxicity
doxorubicin
cancer cells
Modulation
Cynarin
Isoliquiritin
Opis:
Natural polyphenolic compounds produced by plant exhibit many pharmacological effects including antioxidant, chemopreventive as well as anticancer properties. This study was conducted to investigate the effect of cynarin ( from Artichoke, Cynara scolymus) and isoliquiritin (from Licorice, Glycyrrhiza uralensis) on doxorubicin (positive control) cytotoxicity in different cell lines including normal (Fibroblasts MCR-5 and Myoblasts H9c2) and cancer (colorectal HCT-116 and hepatocellular HEP-G2) cell lines. The cytotoxic effect of doxorubicin, isoliquiritin and cynarin alone or in different combination was studied on cancer cell lines as well as normal cell lines. The results obtained indicated that both cynarin and isoliquiritin enhance the cytotoxicity of doxorubicin. Both cynarin and isoliquiritin also reduce the cardiotoxicity of doxorubicin on normal cardiac cell lines. The combination of the three compounds (cynarin, isoliquiritin and doxorubicin) result in decrease the cytotoxicity of doxorubicin, which may indicate the presence of interaction and/or antagonism effect between cynarin and isoliquiritin. Cynarin was found to enhance the growth of (HCT-116 and HEP-G2) this might suggest avoiding use of Artichoke in subjects’ susceptibility for these cancers. All results were evaluated using statistical path and showed significant findings. The mechanism of enhanced doxorubicin’s cytotoxicity by cynarin or isoliquiritin also require further investigation to explain the increasing and/or the decreasing effect of these polyphenolic compounds on cytotoxicity of doxorubicin. The current finding can help to start with safe minimum dose of two or three combination of compounds in the context of clinical trials and practice.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2020, 77, 3; 475-484
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of Non-Binary LDPC Codes for Next Generation Mobile Systems
Autorzy:
Gierszal, H.
Hołubowicz, W.
Kiedrowski, Ł.
Flizikowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/226906.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LDPC
mobile systems
modulation schemes
non-binary
Opis:
A new family of non-binary LDPC is presented that are based on a finite field GF(64). They may be successfully implemented in single-carrier and OFDM transmission system. Results prove that DAVINCI codes allow for improving the system performance and may be considered to be applied in the future mobile system.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 2; 111-116
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Energy Efficient QAM Modulation with Multidimensional Signal Constellation
Autorzy:
Markiewicz, T. G.
Powiązania:
https://bibliotekanauki.pl/articles/227049.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
communication system
QAM modulation
lattice
multidimensional constellations
Opis:
Packing constellations points in higher dimensions, the concept of multidimensional modulation exploits the idea drawn from geometry for searching dense sphere packings in a given dimension, utilising it to minimise the average energy of the underlying constellations. The following work analyses the impact of spherical shaping of the constellations bound instead of the traditional, hyper-cubical bound. Balanced constellation schemes are obtained with the N-dimensional simplex merging algorithm. The performance of constellations of dimensions 2, 4 and 6 is compared to the performance of QAM modulations of equivalent throughputs in the sense of bits transmitted per complex (twodimensional) symbols. The considered constellations give an approximately 0.7 dB to 1 dB gain in terms of BER over a standard QAM modulation.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 2; 159-165
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of the inverse base width modulation effect in HBT transistor with graded SiGe base
Autorzy:
Zaręba, A.
Łukasiak, L.
Jakubowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/308625.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
heterojunction bipolar transistor
SiGe
base width modulation
Opis:
A model of the position of the edge of emitter-base junction in the base and collector current pre-exponential ideality factor in HBT transistor with a SiGe base is presented. The model is valid for transistors with nonuniform profiles of doping and Ge content. The importance of taking into account the dependence of the effective density of states in SiGe on local Ge content and that of electron diffusion coefficient in SiGe on drift field for modeling accuracy is studied.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 3; 88-92
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The simple analysis method of nonlinear frequency distortions in FMCW radar
Autorzy:
Kulpa, K. S.
Wojtkiewicz, A.
Nałęcz, M.
Misiurewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/309080.pdf
Data publikacji:
2001
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
radar
nonlinear frequency distortions
linear frequency modulation
Opis:
The paper presents a simple method for estimating nonlinear frequency distortions of linear frequency modulated (LFM) signals used in FMCW radars. This method, derived from the polynomial model of the nonlinear FM signal phase, is based on finding the maximum of two-dimensional chirp-like transform of the IF video signal. The IF signal is obtained by mixing transmitted FM signal with its delayed copy. Using suggested transform we show that the presented method is able to detect and classify signal distortions.
Źródło:
Journal of Telecommunications and Information Technology; 2001, 4; 26-29
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of potential dangers of Mobile Telecommunication frequencies and modulations
Autorzy:
Bamisaye, A. J.
Powiązania:
https://bibliotekanauki.pl/articles/307594.pdf
Data publikacji:
2013
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
electromagnetic fields
frequency
health
mobile communication
modulation
Opis:
Mobile Telecommunication is one of the fastest growing technologies in the world. The effects of its high frequencies and complex modulations to the exposed population are considered in this paper. Experimental studies examining a variety of effects on all levels of the organism, ranging from effects on single cells to effects which manifest themselves as reactions of the entire body, there have been a number of epidemiological studies in order to establish the possible causal correlations between higher exposures to HF EMFs. Recommendations on the reduction of the effects of EMFs of Mobile Telecommunication on humans was presented.
Źródło:
Journal of Telecommunications and Information Technology; 2013, 2; 30-34
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The sensitivity of vegetation in the lower Tigris basin landscapes to regional and global climate variability
Autorzy:
Alhumaima, Ali S.
Abdullaev, Sanjar M.
Powiązania:
https://bibliotekanauki.pl/articles/35516789.pdf
Data publikacji:
2021
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
climate variability
vegetation
global modulation
precipitation
temperature
Opis:
This study investigates the lower Tigris basin’s the normalized difference vegetation index (NDVI) sensitivity in 2000–2016 to regional climate variability reflected by the monthly precipitation and temperature time series of seven global datasets as well as to four global circulation indices. To examine the effect of climate variability on the different ecosystems, the study area has been classified into 10 smaller natural and anthropogenic landscapes based on landforms and land cover patterns. The preliminary analysis showed that the maximum biological productivity reflected by the NDVI of March and April has the highest correlation (0.5–0.8) to the same cumulative amounts of October–March period total precipitation and January–March period mean temperatures according to all datasets. In addition, this article showed there is a correlation between landscapes’ NDVI and global modulation represented by the September–February state of El Nińo-Southern Oscillation (ENSO) (0.55–0.70) and December state of the dipole mode index (DMI) (0.35–0.72). The significant differences in the original precipitation and temperature levels according to the different datasets have urged the use of normalized time series: z-score of temperatures and analogous six-months the standardized precipitation index (SPI). However, the multiple correlation analysis showed that using ERA-
Źródło:
Scientific Review Engineering and Environmental Sciences; 2021, 30, 1; 159-170
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uniwersalny modulator wektorowy syntezowalny do układu FPGA
Universal vector modulator for FPGA device
Autorzy:
Tarnowski, S.
Piotrowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/156310.pdf
Data publikacji:
2008
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
modulacja wektorowa
transformata Fouriera
FPGA
vector modulation
FFT
Opis:
Przedstawiony artykuł prezentuje wykorzystanie syntezowalnego modulatora wektorowego opisanego w języku wysokiego poziomu. Zastosowanie reprogramowalnego układu logicznego w miejsce układu analogowego umożliwia poprawienie jakości sygnału przez wyeliminowanie wad rozwiązania analogowego. Przykładowym zastosowaniem prezentowanego rozwiązania jest sterowanie polem przyśpieszającym akceleratorów liniowych, jednak może być on wykorzystane w telekomunikacji jako modulator wektorowy.
Using typical analog vector modulator (Fig. 1) in particle accelerator control emphases technical inaccuracies (Fig. 2). There is a possibility of using FPGA device to calculate samples of signal for digital-to-analog converter from vector value. Using this solution is possible to replace analog vector modulator with digital circuit, or even integrate it with controlling device inside one FPGA. FPGAs have not enough speed efficiency for direct calculation of samples. This paper presents solution for sample switching and precalculation of sample values based on inverse Fourier transform. Shown solution consists of multiple parallel shifters (Fig. 3, 4) which can operate at very high frequency.
Źródło:
Pomiary Automatyka Kontrola; 2008, R. 54, nr 8, 8; 582-584
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Shifted Pulse Height Modulated Motor Control for Multiply Actuated Joints to Optimize Operating Characteristics
Autorzy:
Siedel, T.
Bethge, S.
Hild, M.
Powiązania:
https://bibliotekanauki.pl/articles/385220.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
multiple actuators
model-free
frictrion compensation
pulse modulation
Opis:
In this article, we propose two model free control schemes that are based on pulse height modulation using low frequencies with the goal to compensate normal friction effects in drive trains that negatively influence the performance of e.g. a standard PID controller. The first control scheme uses pulse height modulation to especially compensate stick slip effects but increases vibration and noise in the drive train. To reduce such side effects a modified phase shifed pulse height control scheme based on multiple actuated joints is introduced. Both control schemes are compared with a standard linear controller as reference and evaluated by using six quality criteria.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2016, 10, 2; 15-24
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Broadband power electronics controlled current source with analogue control section and output stage based on GaN transistors
Autorzy:
Gwóźdź, M.
Powiązania:
https://bibliotekanauki.pl/articles/377021.pdf
Data publikacji:
2017
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
converter control
GaN transistor
interleaved technique
pulse modulation
Opis:
The paper presents the conception of the power electronics controlled current source based on the sigma–delta modulator (SDM). Due to very high frequency of the SDM output bit stream, in the power stage of inverter the gallium-nitride (GaN) transistors are used. In these circumstances even efficient DSPs are unable, due to limitation of its pass–band of the control path, to obtain right parameters of the output current regulator. So, the regulator is done in the fully analogue manner. As result of these the value of distortions of the inverter output current is much lower, compared to the typical, PWM based, solutions. This benefit is not paid significantly by increase in the system complexity. In work the converter operation basics and results of its simulation model studies are presented.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2017, 91; 55-61
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A model of OFDM based maritime VHF communication system for data exchange
Autorzy:
Valčić, S.
Pogány, T.
Mrak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/260386.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
maritime VHF communications
OFDM modulation
AWGN
SNR
BER
Opis:
In the maritime Very High Frequency (VHF) band, there are no systems for transmitting large amounts of data. Therefore, it is necessary to develop new systems that would modernize the Global Maritime Distress and Safety System (GMDSS), significantly relieve the Automatic Identification System’s (AIS) communication channels, and set guidelines for the development of communication infrastructure of the e-Navigation. In line with this, analytical and simulation models of the maritime VHF data transmission communication system using Orthogonal Frequency Division Multiplexing (OFDM) modulation are worked out in this paper. The achieved data rate, the spectral efficiency and the bit error rate (BER) represent validation parameters on which the results of the analytical and simulation models are evaluated. It is concluded that the application of the digital OFDM modulation in the maritime VHF band may improve the GMDSS system by achieving higher data rates compared to the current terrestrial mandatory systems for data exchange, i.e. Digital Selective Calling (DSC) and AIS.
Źródło:
Polish Maritime Research; 2018, 2; 27-36
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laser frequency counting and frequency modulation width measurement from a FFT signal
Autorzy:
Křen, P.
Powiązania:
https://bibliotekanauki.pl/articles/221880.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
laser
modulation width
frequency measurement
optical frequency synthesizer
Opis:
A new method of optical frequency beat counting based on fast Fourier transform (FFT) analysis is described. Signals with a worse signal-to-noise ratio can be counted correctly comparing to the conventional counting method of detecting each period separately. The systematic error of FFT counting below 10 Hz is demonstrated and can be decreased. Additionally the modulation width of a frequency-stabilized laser with high frequency modulation index can be simultaneously measured during a carrier frequency measurement against an optical frequency synthesizer or other laser.
Źródło:
Metrology and Measurement Systems; 2012, 19, 3; 565-572
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical gradient force of cosh-Gaussian with sine-azimuthal and half-space phase modulation
Autorzy:
Fu, R.
Gao, X.
Shen, H.
Xin, Q
Lu, X.
Guo, L.
Powiązania:
https://bibliotekanauki.pl/articles/173789.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical gradient force
cosh-Gaussian beams
wavefront modulation
Opis:
The optical gradient force distributions in focal plane of cosh-Gaussian beams with sine-azimuthal variation wavefront and half space phase modulation were investigated. Results show that optical gradient force distributions can be affected considerably by the phase retardation of half-space phase modulation, of a phase parameter that indicates the phase change frequency on an increasing azimuthal angle, and beam parameters in cosh terms of the incident beams. Many gradient force patterns occur, including cross-shape, multiple optical trap arrays, multiple-trap wheel, and many kinds of gradient force lines and curves. Symmetry of the whole gradient force pattern can also be altered remarkably. Above results may find wide applications in optical trapping systems.
Źródło:
Optica Applicata; 2013, 43, 4; 719-730
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Focus shaping of the radially polarized Bessel–Gauss beam with a sine-azimuthal variation wavefront
Autorzy:
Gao, X
Zhang, D.
Mei, T.
Fu, R.
Zhuang, S.
Powiązania:
https://bibliotekanauki.pl/articles/174283.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Bessel-Gauss beam
wavefront modulation
vector diffraction theory
Opis:
Focusing properties of the radially polarized Bessel–Gauss beam with a sine-azimuthal variation wavefront was investigated by the vector diffraction theory. The wavefront distribution is the sine function of the azimuthal angle with one phase parameter that indicates the phase change frequency. Results show that the focal pattern can be altered by the phase parameter, and many novel focal patterns may occur, such as multiple dark-foci focal pattern, crescent shape, and wheel shape. For case of a higher phase beam, the whole focal pattern turns on a symmetric wheel shape with multiple reduplicate intensity elements. When the phase parameter is an odd number, the number of reduplicate elements equals the phase parameter, while when the phase parameter is an even number, the number of reduplicate elements is two times the phase parameter. In addition, the effect of the phase parameter on the focal pattern is more considerable than that of the beam parameter under low numerical aperture. Under higher numerical aperture, the effect of the beam parameter on the focal pattern gets stronger.
Źródło:
Optica Applicata; 2013, 43, 3; 567-582
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Enhancement of Chaotic Error Correction Coding Using Consecutive Sequences
Autorzy:
Sahar, Asaad H.
Abdullah, Hikmat N.
Saed, Thamir R.
Powiązania:
https://bibliotekanauki.pl/articles/24200739.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
chaos communication
DCSK modulation
error correction
suboptimal receiver
Opis:
The use of chaotic dynamics for error correction is the subject of extensive research, as the approach allows to avoid the use of redundant data. This work proposes a new technique for non-coherent chaos communications for modifying error-correction depending on chaotic dynamics. In the proposed system, there are two consecutive sequences created from a comparable chaotic map, with the second series being created as the latest value of the initial one. Generation of a sequential chaotic sequence with a comparable chaotic dynamic delivers additional information to the receiver, allowing it to appropriately recover information and, hence, facilitate the receiver’s bit-error performance. For error correction and for detecting the symbol that is transmitted, a suboptimal technique based on the nearest distance between chaotic map trajectories over the n-dimensional sequence received is utilized. Simulation results show that the proposed error correction approach improves Eb/N0 as the dimension of the trajectory map increases, indicating that the method improves overall error correction performance. With the dimension of 4, a gain of 0.8 dB in Eb/N0 is achieved compared with an approach without any error-correcting schemes, at the bit-error probability of 10−3.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 2; 10--16
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of all-optical logic XOR gate based on linear optical amplifier cross-gain modulation
Autorzy:
Li, X
Jin, J
Li, H
Zhang, Q
Powiązania:
https://bibliotekanauki.pl/articles/174514.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
linear optical amplifier
cross-gain modulation
XOR gate
Opis:
All-optical logic is the key to future high speed and large capacity optical transmission, the realization of optical packet switching and optical computing, and it has a very profound influence on the development of future optical communication. A linear optical amplifier as a new type of semiconductor optical amplifier, which has a good gain characteristic, has better signal performance than a traditional semiconductor optical amplifier in the wavelength conversion. This article presents a numerical simulation model of all-optical logic XOR gate and its logic operation based on cross-gain modulation of linear optical amplifier, and has also completed some of the basic logic operations, including AND, OR, NOT operations.
Źródło:
Optica Applicata; 2015, 45, 4; 447-457
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modulation index optimization for wavelength modulation spectroscopy
Autorzy:
Mohammadi, M. J.
Khorsandi, A.
Ghavami, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/949416.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wavelength modulation spectroscopy
NIR laser spectroscopy
molecular spectroscopy
Opis:
In this work, the second-harmonic component of wavelength modulation spectroscopy is simulated for R(22) CO2 absorption line to investigate the effect of gas temperature and pressure on the modulation index. We found that the optimum value of modulation index, that is 2.2, is not affected by temperature but gas pressure will change the optimized modulation index. Specifically, when the gas pressure decreased to lower pressures of less than 100 mbar, the modulation index is also decreased and tended exponentially to about two. Accordingly, the optimum value of modulation index is recalculated for a range of CO2 gas pressures to establish a nearly zero pressure deviation in the spectroscopy of very low pressure samples.
Źródło:
Optica Applicata; 2016, 46, 4; 639-650
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved space vector modulation strategy for common-mode voltage reduction in matrix rectifier
Autorzy:
Liu, X.
Zhang, Q.
Hou, D.
Powiązania:
https://bibliotekanauki.pl/articles/950664.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
matrix converter
space vector modulation
common-mode voltage
Opis:
The matrix rectifier modulated by the classical space vector modulation (SVM) strategy generates common-mode voltage (CMV). The high magnitude and high du/dt of the CMV causes serious problems such as motor damage, electromagnetic noise and many others. In this paper, an improved SVM strategy is proposed by replacing the zero vectors with suitable couple of active ones that substantially eliminate the CMV. Theoretical analysis proves that the proposed strategy can reduce the amplitude of the CMV to half of the original value. In addition, the quality of the input and output waveforms is not affected by extra active vectors. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposed strategy are shown.
Źródło:
Archives of Electrical Engineering; 2014, 63, 1; 93-106
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Synchronization Method for Transmission Systems with Variable Length of Bits
Autorzy:
Godek, J.
Golański, R.
Kołodziej, J.
Stępień, J.
Powiązania:
https://bibliotekanauki.pl/articles/226590.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
delta modulation
adaptation
non-uniform sampling
synchronization
codec
Opis:
Based on the Spartan 3E evaluation module, a flexible platform for the implementation of different algorithms for A/D conversion was developed. The aim of presented work was to improve the concept of the sampling rate adaptation to the input signal rate of change in terms of practical issues including synchronization of delta codecs. The new, original synchronization method, useful in systems dedicated for transmission of variable duration of bits was proposed and experimentally verified. Performed measures and observations have shown elimination of the synchronization lose phenomenon.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 1; 31-36
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impacts of modulation for direct payments in Hungary
Wpływ modulacji na bezposrednie płace na Węgrzech
Autorzy:
Vasary, M.
Molnar, J.
Zsolt, B.
Powiązania:
https://bibliotekanauki.pl/articles/868774.pdf
Data publikacji:
2013
Wydawca:
The Polish Association of Agricultural and Agribusiness Economists
Tematy:
modulation
direct payment
payment
subsidy redeployment
calculation
Hungary
Opis:
The redeployment of subsidies through modulation was a new element in the system of Hungarian agricultural support in the premium year of 2012. In harmony with EU principles, it has become possible (within Hungarian implementation) to create a system which enables the radical moderation of actual volumes of subsidy redeployment resulting from modulation. The basis of model calculations was created by the finalized data of ARDA about payments in the premium year of 2011. Following the running of calculations, it can be confirmed that the implementation of the Hungarian method has resulted in reduced payments only in the case of 2% of all farmers eligible for direct subsidies, and about 10% of those who are actually involved in payment reduction.
Nową częścią węgierskiego systemu wsparcia rolnictwa w roku składkowym 2012 było przegrupowanie dotacji poprzez modulację. Na Węgrzech możliwe stało się stworzenie systemu, który zgodnie z zasadami UE umożliwiał radykalne obniżenie aktualnej wysokości przegrupowania dotacji będącej wynikiem modulacji. Podstawą do obliczenia modelu były dane ARDA na temat wpłat za rok składkowy 2011. Można potwierdzić, że wprowadzenie węgierskiej metody skutkowało zmniejszeniem składek tylko w przypadku 2% wszystkich rolników, którym przysługują bezpośrednie dotacje i ok. 10% w przypadku tych, którzy rzeczywiście przyczyniają się do zmniejszenia składek.
Źródło:
Roczniki Naukowe Stowarzyszenia Ekonomistów Rolnictwa i Agrobiznesu; 2013, 15, 4
1508-3535
2450-7296
Pojawia się w:
Roczniki Naukowe Stowarzyszenia Ekonomistów Rolnictwa i Agrobiznesu
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impulsive Sound Detection Directly in Sigma-Delta Domain
Autorzy:
Miranda, I. D. dos S.
Lima, A. C. de C.
Powiązania:
https://bibliotekanauki.pl/articles/176966.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
impulsive signal detection
sigma-delta modulation
discrete cosine transform
Opis:
Recent implementations of Sigma-Delta (ΣΔ) converters have achieved low cost, low power consumption, and high integration while maintaining resolution as high as in Nyquist-rate converters. However, its usage implies demodulating the source signal delivered from ΣΔ modulation to Pulse-Code Modulation (PCM) on a pre-processing stage. This work proposes an algorithm based on Discrete Cosine Transform for impulsive signal detection to be applied directly on a modulated ΣΔ bitstream, targeting to reduce computational cost in acoustic event detection applications such as gunshot recognition systems. From pre-recorded impulsive sounds in ΣΔ format, it has been shown that the new method presents a similar error rate in comparison with traditional energy-based approaches in PCM, meanwhile, it reduces significantly the number of operations per unit time.
Źródło:
Archives of Acoustics; 2017, 42, 2; 255-261
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conducted EMI mitigation in switched mode dc-dc converters by spread spectrum techniques
Autorzy:
Knitter, A.
Łuszcz, J.
Chrzan, P. J.
Powiązania:
https://bibliotekanauki.pl/articles/262735.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
spread spectrum
carrier frequency modulation
EMI suppression
electromagnetic compatibility
Opis:
In this paper effectiveness of spread spectrum modulation techniques to the electromagnetic interference (EMI) suppression is investigated. Comparative evaluation of spread spectrum methods is reviewed and demonstrated with the aid of function generator and EMI receiver. Obtained results indicate advantageous features of random carrier frequency modulation (CFM), which results in more steady spectral distribution. For a switch mode dc-dc converter, random and periodical sinusoidal CFM is systematically tested. Based on disturbance voltage measurements using Line Impedance Stabilization Network (LISN) and EMI receiver, conducted emission spectra are evaluated in function of the defined randomness index R and frequency range. For the acceptable range of R variations up the 20dB EMI suppression level was reached.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2005, 11, 2; 49-55
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy Model of 16PSK and 16QAM Modulation
Autorzy:
Butkiewicz, B. S.
Powiązania:
https://bibliotekanauki.pl/articles/227079.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fuzzy modulation
BER
possibility
probability
PSK
QAM
noise
signal
Opis:
In the paper, a concept of Additive Fuzzy Noise (AFN) channel is introduced. The theoretical equations are derived for Bit Error Rate (BER) and Symbol Error Rate (SER) with some digital modulation scheme in the AFN channel. Following modulations are considered: Phase Shift Keying (16PSK), Quadrature Amplitude Modulation (16QAM). The fuzzy approach to these modulations is presented. The BER and SER values are calculated using possibility theory. The results obtained by fuzzy noise model are compared with conventional approach, where probability models of the noise are used.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 4; 437-442
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnosis and Therapy of Respiratory and Phonatory Disorders in Dysartrhia. Case Studies
Diagnoza i terapia zaburzeń oddechowo-fonacyjnych w dyzartrii. Studia indywidualnych przypadków
Autorzy:
Szewczyk, Beata
Powiązania:
https://bibliotekanauki.pl/articles/667489.pdf
Data publikacji:
2019
Wydawca:
Wydawnictwo Uniwersytetu Śląskiego
Tematy:
dysarthria
respiration
phonation
voice modulation
neurologopaedic diagnosis and therapy
Opis:
This article presents the exemplary types of dysarthria with its characteristic respiration, phonation, and prosody disorders. The author examined the voice capabilities of three patients, aged 52, 74 and 81, respectively, described them, and composed short session programmes in voice therapy (comprised of three meetings) adapted to their individual needs. The author carried out the part of the therapy and then listed tendencies resurfacing during the exercises performed by the patients. Finally, the expected effects of further exercises (following previously applied methods) were presented.
Źródło:
Logopedia Silesiana; 2019, 8; 400-434
2300-5246
2391-4297
Pojawia się w:
Logopedia Silesiana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and simulation of novel stepped DC coupled quasi Z-Multilevel Inverter for single phase systems
Autorzy:
Meenakshi, T.
Suthanthira Vanitha, N.
Powiązania:
https://bibliotekanauki.pl/articles/140968.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multilevel inverter
shoot through
quasi Z-Source
modulation index
Opis:
This paper presents the modeling and simulation of a novel topology of quasi Z-Multilevel Inverter with stepped DC input. The proposed inverter incorporates a simple switching technique with reduced component count and is aimed at producing boosted multilevel output AC voltage. The inverter consists of two stages and the buck /boost operation is obtained by varying the shoot through period of the pulses obtained by maximum constant boost control with third harmonic injection. With all the advantages of the quasi Z-network, the proposed inverter eliminates the fly back diodes and capacitors present in a conventional Z-Multilevel Inverter. Further the stress on the devices is less which leads to reduction in component value and hence the cost. The novel stepped DC coupled Single Phase quasi Z-Multilevel Inverter is modeled and simulated in the MATLAB – SIMULINK environment and its performance is analyzed for varying input and switching conditions. The voltage and current waveforms across each stage of the inverter is analyzed and the results are presented for different levels of input.
Źródło:
Archives of Electrical Engineering; 2016, 65, 3; 437-448
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis of variable speed multiphase induction motor with pole phase modulation
Autorzy:
Liu, H.
Wang, J.
Zhang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/140991.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
induction motor (IM)
pole phase modulation (PPM)
efficiency
FEM
Opis:
The pole phase modulation (PPM) technique is an effective method to extend speed range and torque capabilities for an integrated starter and hybrid electric vehicles applications. In this paper, the five pole-phase combination types of a multiphase induction motor (IM) with 36 stator slots and 36 stator conductors are presented and compared quantitatively by using the time-stepping finite element method (TS-FEM). The 36 stator conductors of the proposed multiphase IM are fed by a 36 leg inverter and the current phase angle and amplitude of each stator conductor can be controlled independently. This paper focuses on the winding connection, the PPM technique and the performance comparative analysis of each pole-phase combination types of the proposed multiphase IM. The flux distribution, air-gap flux density, output torque, core losses and efficiency of five pole-phase combination types have been investigated.
Źródło:
Archives of Electrical Engineering; 2016, 65, 3; 425-436
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of viscosity on the far-field diffraction pattern of spatial self-phase modulation
Autorzy:
Nibu, A. G.
Silpa, S. S.
Ardra, S. N.
Anisha, M. M.
Ambika, D.
Powiązania:
https://bibliotekanauki.pl/articles/174699.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
self-phase modulation
nonlinear refractive index
chlorophyll
engine oil
Opis:
Effect of viscosity of a liquid on the far-field diffraction pattern due to spatial self-phase modulation is investigated. Chlorophyll extract in acetone at different concentrations is used as the low viscous nonlinear samples and commercial engine oils, synthetic and natural. It is also used as high viscous media. In the case of chlorophyll solution, the self-induced diffraction ring pattern in the far-field is a series of circular rings at the beginning; but later it is transformed to half circular symmetry. But for the high viscous engine oils we have observed circular fringes and there is no time dependent structural variation in the pattern. The coefficient of the intensity dependent nonlinear refractive index for all the liquid samples is evaluated.
Źródło:
Optica Applicata; 2017, 47, 4; 591-599
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power transfer analysis in a single phase dual active bridge
Autorzy:
Barlik, R.
Nowak, M.
Grzejszczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/201137.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bidirectional active bridge - DAB
power losses
shift phase modulation
Opis:
This paper presents an analysis of the power transfer between two DC circuit by use a single phase galvanically isolated dual active bridge - DAB. The analytical description of instantaneous values of the currents in both DC and in AC circuits of the DAB is done. The influence of the dead time as well as voltage drops across the transistors and diodes of the bridges is examined. The different relations between voltages of the DC circuits coupled through DAB and various phase shift ratios are considered. The analytical relations describing the average values of the currents in DC circuits are derived. These currents can be used to predict the power in both DC circuits and power losses generated in semiconductor devices of the converter. It is assumed that the voltage drops across these devices in conduction states are constant. The calculation of the transferred power as well as power losses and energy efficiency for the DAB converter power rated 5600 VA which is used to energy transfer between DC circuits 280 V and 51 V±20% is presented. The proposed relations and calculation results can be useful for preliminary evaluation of power losses generated in semiconductor devices and for design of the cooling system. Due to the high switching frequency of 100 kHz, the phase shift modulation for the control of DAB is used. To validate the theoretical investigations a few experimental results are presented.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 4; 809-828
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of different modulation techniques performances in an underground multiuser communications scenario
Autorzy:
Badescu, A.-M.
Powiązania:
https://bibliotekanauki.pl/articles/106166.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
modulation techniques
commercial communication systems
CDMA
16-QAM
QPSK
Opis:
The potential use of typical commercial communication systems with ultra high frequencies for the underground emergency/military situations will be investigated, as commercial systems have already a fully developed market that makes them cheap and reliable. The possible usage of broadband techniques like CDMA in the direct sequence will be studied because most commercial communication systems have already been designed to support multiple users, as the underground propagation has many possible applications. The performances of both modulation techniques are evaluated from the point of view of the quality of the signals, power spectral density and the effect that the propagation medium has on the transmitted signals such that the best modulation technique is determined. The 16QAM and QPSK modulations (two of the most popular modulation techniques in the terrestrial wireless system) are compared in a scenario where a number of underground sources share the same physical channel (and antenna) - the receiver is placed at the ground level so the generated signals must propagate through the dielectric layer in order to reach it. The transmitted power, electric and magnetic fields as well as occupied bandwidth are also calculated.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2012, 12, 2; 73-85
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Torque ripple reduction in BLDC motor based ona PWM technique for open-end winding
Autorzy:
Baszyński, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/1841368.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
BLDC motor
open-end winding
PWM technique
unipolar modulation
Opis:
The article presents a modulation method for BLDC motors with unconnected windings. This method uses two full bridges (or three 12-switch H-bridges). The useof the described modulation enables reducing the motor current variable and increasing (fourfold in relation to the switching frequency) the motor current ripple frequency. Themost important benefit of using a 12-switch inverter is the twofold reduction of the dc-linkvoltage while maintaining the rated rpm (voltage reduction in comparison to a typical supplymethod). A voltage reduction causes a reduction in losses on semi-conductor elements. Thearticle also demonstrates that the proposed modulation technique significantly shortens thetime of current commutation between windings.
Źródło:
Archives of Electrical Engineering; 2021, 70, 1; 5-23
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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