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Wyświetlanie 1-15 z 355
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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
Wyświetlanie 1-15 z 355

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