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    Wyświetlanie 1-26 z 26
    Tytuł:
    Zastosowanie filtrów wygładzających do estymacji współczynnika SNR w sygnałach zakłóconych szumem o rozkładzie normalnym
    Application smoothing filters to estimate the SNR in the noise signals disturbed of the normal distribution
    Autorzy:
    Mikołajczak, G.
    Pęksiński, J.
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/377657.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
    Tematy:
    filtry wygładzające
    SNR
    Opis:
    W pracy przedstawiono metodę estymacji współczynnika SNR opartą o wybrane metody wygładzania sygnałów przy założeniu, że w procesie filtracji tłumiony jest tylko szum. Znajomość współczynnika redukcji szumu pozwala wyznaczyć wartość estymowanej wielkości. Obliczenia i symulacje wykonano dla sygnału harmonicznego zakłóconego szumem o rozkładzie normalnym.
    The paper presents a method of estimating the SNR based on the selected method of smoothing signals on the assumption that the filtration process is suppressed only noise. Knowledge of Noise Reduction Coefficient lets you determine the value of the estimated size. Calculations and simulations were performed in the harmonic signal noise disturbed the normal distribution.
    Źródło:
    Poznan University of Technology Academic Journals. Electrical Engineering; 2016, 88; 101-108
    1897-0737
    Pojawia się w:
    Poznan University of Technology Academic Journals. Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Subcarrier Gain Based Power Allocation in Multicarrier Systems
    Autorzy:
    Abd-Elnaby, M.
    Sedhom, G. G.
    Messiha, N. W.
    Abd El-Samie, F. E.
    Zhu, X.
    Powiązania:
    https://bibliotekanauki.pl/articles/958110.pdf
    Data publikacji:
    2014
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    GPA
    OFDM
    QAM
    SNR
    Opis:
    The Orthogonal Frequency Division Multiplexing (OFDM) transmission is the optimum version of the multicarrier transmission scheme, which has the capability to achieve high data rate. The key issue of OFDMsystem is the allocation of bits and power over a number of subcarriers. In this paper, a new power allocation algorithm based on subcarrier gain is proposed to maximize the bit rate. For OFDM systems, the Subcarrier Gain Based Power Allocation (SGPA) algorithm is addressed and compared with the standard Greedy Power Allocation (GPA). The authors demonstrate by analysis and simulation that the proposed algorithm reduces the computational complexity and achieves a near optimal performance in maximizing the bit rate over a number of subcarrier.
    Źródło:
    Journal of Telecommunications and Information Technology; 2014, 1; 62-67
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estymacja SNR przy użyciu filtrów cyfrowych dla łączy światłowodowych
    SNR estimation using digital filters for fiber optic lines
    Autorzy:
    Żegliński, Grzegorz
    Pęksiński, Jakub
    Mikołajczak, Grzegorz
    Powiązania:
    https://bibliotekanauki.pl/articles/377070.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
    Tematy:
    dyspersja chromatyczna
    estymacja SNR
    Opis:
    W pracy przedstawiono metodę estymacji SNR przy pomocy cyfrowych filtrów wygładzających. Na podstawie właściwości tych filtrów w procesie przetwarzania sygnałów zaproponowano metodę obliczania współczynnika SNR, a także parametrów rozkładu zakłócenia. Metodę sprawdzono do oceny zakłóceń transmisyjnych w światłowodzie jednomodowym przepływności 1 Gbit/s dla odcinka 53 km.
    The paper presents the SNR estimation method using digital smoothing filters. Based on the properties of these filters in the signal processing process, the method of calculating the SNR coefficient as well as the disturbance distribution parameters were proposed. The method was checked to the estimate of degradation in the single mode fiber (SMF) of 1 Gbit/s bit rate for the transmission distance – 53 km.
    Źródło:
    Poznan University of Technology Academic Journals. Electrical Engineering; 2019, 97; 191-202
    1897-0737
    Pojawia się w:
    Poznan University of Technology Academic Journals. Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    PC-based high frequency imaging system with coded excitation
    Autorzy:
    Lewandowski, M.
    Nowicki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/331588.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    coded transmission
    SNR
    FPGA
    Opis:
    Coded transmission is a technique that gives significant improvement in SNR and enables higher contrast imaging without sacrificing the resolution. A novel HF (20-35 MHz) ultrasound real-time imaging system for research and evaluation of the coded transmission was developed. The digital programmable coder-digitizer module based on the field programmable gate array (FPGA) chip supports arbitrary waveform coded transmission and RF echoes sampling up to 200 MSPS. A novel balanced software architecture supports real-time RF processing and display at rates up to 30 frames/sec. The system was used to gather data for sine burst and 16-bit Golay code excitation using a single element scanning head with thick film focused spherical transducer 25 MHz center frequency and 56% system bandwidth. SNR gain for the Golay codes (referenced to single burst) of 15 dB for 20 MHz and 16 dB for 35 MHz were obtained. In water the axial resolution for both single burst and the Golay codes was the same FWMH=20 ns at 20 MHz and FWMH=15 ns at 35 MHz. The presented system is a practical and low cost implementation of coded excitation technique in HF ultrasound imaging.
    Źródło:
    Hydroacoustics; 2008, 11; 239-247
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estymacja współczynnika SNR w sygnale harmonicznym przy pomocy wygładzania wykładniczego
    The estimation of SNR in the harmonic signal using the exponential smoothing
    Autorzy:
    Kowalski, J.
    Pęksiński, J.
    Mikołajczak, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/252968.pdf
    Data publikacji:
    2015
    Wydawca:
    Instytut Naukowo-Wydawniczy TTS
    Tematy:
    współczynnik SNR
    wygładzanie
    filtracja
    szum
    estymacja
    SNR factor
    smoothing
    filtering
    noise
    estimation
    Opis:
    W pracy przedstawiono metodę estymacji współczynnika SNR opartą o wygładzanie wykładnicze i założenie, że w procesie filtracji tłumiony jest tylko szum. Znajomość współczynnika redukcji szumu pozwala wyznaczyć wartość estymowanej wielkości.
    The paper presents the SNR estimation method based on exponential smoothing, and the assumption that the filtration process only noise is suppressed. Knowledge of Noise Reduction Coefficient lets you determine the value of the estimated size.
    Źródło:
    TTS Technika Transportu Szynowego; 2015, 12; 834-836, CD
    1232-3829
    2543-5728
    Pojawia się w:
    TTS Technika Transportu Szynowego
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Link Quality and Energy Aware Geographical Routing in MANETs using Fuzzy Logics
    Autorzy:
    Mishra, P.
    Gandhi, C.
    Singh, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/308336.pdf
    Data publikacji:
    2016
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    GPSR
    LAR
    MANET
    RSSI
    SINR
    SNR
    Opis:
    In literature, varieties of topology and geographical routing protocols have been proposed for routing in the MANETs. It is widely accepted that the geographical routings are a superior decision than topological routings. Majority of geographical routing protocols assume an ideal network model and choose the route that contains minimum number of hops. However, in reality, nodes have limited battery power and wireless links are additionally unreliable, so they may highly affect the routing procedure. Thus, for reliable data transmission, condition of the network such as link quality and residual energy must be considered. This paper aims to propose a novel multi-metric geographical routing protocol that considers both links-quality and energy metric along with progress metric to choose the next optimal node. The progress is determined by utilizing greedy as well as compass routing rather than pure greedy routing schemes. To combine these metrics, fuzzy logics are used to get the optimal result. Further, the protocol deals with “hole” problem and proposes a technique to overcome it. Simulations show that the proposed scheme performs better in terms of the packet delivery ratio, throughput and residual energy than other existing protocols.
    Źródło:
    Journal of Telecommunications and Information Technology; 2016, 3; 5-17
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Studying and Modeling the Performance of the TCM-STBC Systems in the Rayleigh Channel
    Autorzy:
    Bendelhoum, Mohammed Sofiane
    Lahcene, Mohamed Rida
    Menezla, Fayssal
    Elarbi, Abderraouf
    Powiązania:
    https://bibliotekanauki.pl/articles/1839476.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    BER
    MIMO
    SNR
    STBC
    STTC
    TCM
    TCM-STBC
    Opis:
    Multiple-input multiple-output (MIMO) systems will play an important role in future generations of wireless networks. Space-time block code (STBC) and space-time trellis code (STTC) are two techniques that may be used in multi-antenna radio systems. This paper aims, most importantly, to study the performance of STBC systems at different values of such parameters as spectral efficiency, matrix codes and constellations. A performance comparison between STBC and STTC schemes is performed. In order to show the efficiency of the system’s ability to communicate with uncoded and coded transmission structures over AWGN and Rayleigh channels, the trellis-coded modulation (TCM) is introduced. The results obtained show that the proposed TCM-STBC system model, using one and two receiving antennas, improves the performance of Rayleigh channel communication systems at 9.5 dB and 11.5 dB for a BER of 10−5.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 1; 1-7
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    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:
    Hardware Implementation of MISO on Orthogonal Frequency Division Multiplexing Platform with the Help of Alamouti Algorithm
    Autorzy:
    Kilaru, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/226220.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    MISO
    SISO
    FPGA
    Xilinx
    BER
    SNR
    Alamouti
    LTE
    Opis:
    Many software based OFDM techniques were proposed from last half decade to improve the performance of the system. This paper tried to implement the same with Hardwar implementation. We created Hardware based MISO platform with OFDM. We implemented Alamouti algorithm on this test bed. The test bed is implemented with the help of Field Programmable Gate Array (FPGA). The test bed is functionalized with the help of FPGA through Xilinx based system generator for DSP. In this paper we considered the 2×1 MISO implementation with Alamouti algorithm. The simulation results showed that BER and SNR are considerably high for MISO than SISO. The results also proved that proposed OFDM based Alamouti implementation for MISO is excellent in all performance criterions.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 2; 137-143
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Studying and Modeling the Performance of the TCM-STBC Systems in the Rayleigh Channel
    Autorzy:
    Bendelhoum, Mohammed Sofiane
    Lahcene, Mohamed Rida
    Menezla, Fayssal
    Elarbi, Abderraouf
    Powiązania:
    https://bibliotekanauki.pl/articles/1839490.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    BER
    MIMO
    SNR
    STBC
    STTC
    TCM
    TCM-STBC
    Opis:
    Multiple-input multiple-output (MIMO) systems will play an important role in future generations of wireless networks. Space-time block code (STBC) and space-time trellis code (STTC) are two techniques that may be used in multi-antenna radio systems. This paper aims, most importantly, to study the performance of STBC systems at different values of such parameters as spectral efficiency, matrix codes and constellations. A performance comparison between STBC and STTC schemes is performed. In order to show the efficiency of the system’s ability to communicate with uncoded and coded transmission structures over AWGN and Rayleigh channels, the trellis-coded modulation (TCM) is introduced. The results obtained show that the proposed TCM-STBC system model, using one and two receiving antennas, improves the performance of Rayleigh channel communication systems at 9.5 dB and 11.5 dB for a BER of 10−5.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 1; 1-7
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A new low SNR underwater acoustic signal classification method based on intrinsic modal features maintaining dimensionality reduction
    Autorzy:
    Ju, Yang
    Wei, Zhengxian
    Li, Huangfu
    Feng, Xiao
    Powiązania:
    https://bibliotekanauki.pl/articles/259300.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    acoustic
    low SNR
    signal classification
    feature maintain
    dimension reduction
    Opis:
    The classification of low signal-to-noise ratio (SNR) underwater acoustic signals in complex acoustic environments and increasingly small target radiation noise is a hot research topic. . This paper proposes a new method for signal processing—low SNR underwater acoustic signal classification method (LSUASC)—based on intrinsic modal features maintaining dimensionality reduction. Using the LSUASC method, the underwater acoustic signal was first transformed with the Hilbert-Huang Transform (HHT) and the intrinsic mode was extracted. the intrinsic mode was then transformed into a corresponding Mel-frequency cepstrum coefficient (MFCC) to form a multidimensional feature vector of the low SNR acoustic signal. Next, a semi-supervised fuzzy rough Laplacian Eigenmap (SSFRLE) method was proposed to perform manifold dimension reduction (local sparse and discrete features of underwater acoustic signals can be maintained in the dimension reduction process) and principal component analysis (PCA) was adopted in the proces of dimension reduction to define the reduced dimension adaptively. Finally, Fuzzy C-Means (FCMs), which are able to classify data with weak features was adopted to cluster the signal features after dimensionality reduction. The experimental results presented here show that the LSUASC method is able to classify low SNR underwater acoustic signals with high accuracy.
    Źródło:
    Polish Maritime Research; 2020, 2; 187-198
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Improved Downlink MC-CDMA System for Effcient Image Transmission
    Autorzy:
    Bendelhoum, M. S.
    Djebbari, A.
    Boukli-Hacene, I.
    Taleb-Ahmed, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/308187.pdf
    Data publikacji:
    2017
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    data compression
    MC-CDMA
    MSSIM
    performance evaluation
    PSNR
    SNR
    SPIHT
    Opis:
    Image compression is an essential stage of the data archiving and transmitting process, as it reduces the number of bits and the time required to complete the transmission. In this article, a study of image transmission over the Multi-Carrier Code Division Multiple Access (MC-CDMA) downlink system is presented. The solution proposed relies on source coding combined with channel coding. The Discrete Wavelet Transform (DWT) method is used in conjunction with the SPIHT coder to compress the image, then the data generated is transmitted with the MC-CDMA technique over a noisy channel. The results show that image transmissions performed over MC-CDMA using the SPIHT model are better than the traditional approach like MC-CDMA in the AWGN channel.
    Źródło:
    Journal of Telecommunications and Information Technology; 2017, 4; 5-16
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Periodic signal detection with using duffing system poincare map analysis
    Autorzy:
    Martynyuk, V
    Fedula, M
    Balov, O
    Powiązania:
    https://bibliotekanauki.pl/articles/102192.pdf
    Data publikacji:
    2014
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    periodic signal detection
    chaotic system
    Duffing oscillator
    Poincare sections
    SNR
    Opis:
    In this article the periodic signal detection method on the base of Duffing system chaotic oscillations analysis is presented. This work is a development of the chaos-based signal detection technique. Generally, chaos-based signal detection is the detection of chaotic-to-periodic state transition under input periodic component influence. If the in¬put periodic component reaches certain threshold value, the system transforms from chaotic state to periodic state. The Duffing-type chaotic systems are often used for such a signal detection purpose because of their ability to work in chaotic state for a long time and relatively simple realization. The main advantage of chaos-based signal detection methods is the utilization of chaotic system sensitivity to weak signals. But such methods are not used in practice because of the chaotic system state control problems. The method presented does not require an exact system state control. The Duffing system works continuously in chaotic state and the periodic signal detection process is based on the analysis of Duffing system Poincare map fractal structure. This structure does not depend on noise, and therefore the minimum input signal-to-noise ratio required for periodic signal detection is not limited by chaotic system state control tolerance.
    Źródło:
    Advances in Science and Technology. Research Journal; 2014, 8, 22; 26-30
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Viability and genetic diversity of Populus nigra population from riparian forest in SNR Gornje Podunavlje
    Autorzy:
    Čortan, Dijana
    Tubić, Bojan
    Powiązania:
    https://bibliotekanauki.pl/articles/956812.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Instytut Dendrologii PAN
    Tematy:
    black poplar
    viability assessment
    genetic diversity
    ssr markers
    snr upper danube
    Opis:
    Populus nigra L. is one of the rarest and most endangered tree species in Western and Central Europe. Its genetic diversity is of great importance in enabling a native riparian population to survive and reproduce under changing environmental conditions. The aim of this research was assessment of P. nigra viability in one of the best preserved riparian ecosystems in Europe, Special Nature Reserve “Gornje Podunavlje” (Upper Danube), Serbia. Additionally, the analysis of the genetic diversity was made to support the effective conservation in the future. During our study, we have mapped 931 P. nigra trees, which were used for the assessment of present native population. Furthermore, we used 14 microsatellite markers to assess the genetic structure of this this population. Viability assessment showed considerable occurrence of P. nigra in the research area, even though the results show fragmentation. P. nigra occurs mostly individually or in small groups of trees, and has a non-sustainable age structure due to insufficient or lacking regeneration. Despite the limited size of the studied population, the apparent overall genetic diversity was high (He = 0.759) and comparable to other known native populations of P. nigra along the Danube basin. However, the results also confirmed existence of recent bottleneck effect. Significantly positive and quite high Fis value (0.147) was noted, which may be ascribed to the “Wahlund effect” because of the population substructure that was revealed by the STRUCTURE analysis (K=2). Although results say that coverage of native stands is not so promising, most of selected trees within our research assessed showed good viability with potential for natural reproduction However, the problem is that suitable areas for natural seedling establishment are scarce and with that gene flow is probably limited. The fragmentation of the area must be reduced and isolated stands must be interlinked as there is need to create larger non-fragmented areas.
    Źródło:
    Dendrobiology; 2017, 78; 157-167
    1641-1307
    Pojawia się w:
    Dendrobiology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Speech Enhancement Based on the Multi-Scales and Multi-Thresholds of the Auditory Perception Wavelet Transform
    Autorzy:
    Tao, Z.
    Zhao, H. M.
    Zhang, X-J.
    Wu, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/177021.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    speech enhancement
    low SNR
    auditory perception wavelet transform
    unvoiced enhancement
    masking effect
    Opis:
    This paper proposes a speech enhancement method using the multi-scales and multi-thresholds of the auditory perception wavelet transform, which is suitable for a low SNR (signal to noise ratio) environment. This method achieves the goal of noise reduction according to the threshold processing of the human ear’s auditory masking effect on the auditory perception wavelet transform parameters of a speech signal. At the same time, in order to prevent high frequency loss during the process of noise suppression, we first make a voicing decision based on the speech signals. Afterwards, we process the unvoiced sound segment and the voiced sound segment according to the different thresholds and different judgments. Lastly, we perform objective and subjective tests on the enhanced speech. The results show that, compared to other spectral subtractions, our method keeps the components of unvoiced sound intact, while it suppresses the residual noise and the background noise. Thus, the enhanced speech has better clarity and intelligibility.
    Źródło:
    Archives of Acoustics; 2011, 36, 3; 519-532
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Investigation of the MIMO Space Time Block Code Based Selective Decode and Forward Relaying Network over η–µ Fading Channel Conditions
    Autorzy:
    Shankar, Ravi
    Raman, V. V. Raghava
    Rane, Kantilal Pitamber
    Sarojini, B. K.
    Neware, Rahul
    Powiązania:
    https://bibliotekanauki.pl/articles/2058506.pdf
    Data publikacji:
    2022
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    5G
    MIMO
    MRC
    non-homogeneous fading channel
    PEP
    S-DF
    SNR
    Opis:
    In this paper, we examine the end-to-end average pairwise error probability (PEP) and output probability (OP) performance of the maximum ratio combining (MRC) based selective decode and forward (S-DF) system over an η–µ scattering environment considering additive white Gaussian noise (AWGN). The probability distribution function (PDF) and cumulative distribution function (CDF) expressions have been derived for the received signal-to-noise (SNR) ratio and the moment generating function (MGF) technique is used to derive the novel closed-form (CF) average PEP and OP expressions. The analytical results have been further simplified and are presented in terms of the Lauricella function for coherent complex modulation schemes. The asymptotic PEP expressions are also derived in terms of the Lauricella function, and a convex optimization (CO) framework has been developed for obtaining optimal power allocation (OPA) factors. Through simulations, it is also proven that, depending on the number of multi-path clusters and the modulation scheme used, the optimized power allocation system was essentially independent of the power relation scattered waves from the source node (SN) to the destination node (DN). The graphs show that asymptotic and accurate formulations are closely matched for moderate and high SNR regimes. PEP performance significantly improves with an increase in the value of η for a fixed value of µ. The analytical and simulation curves are in close agreement for medium-to-high SNR values.
    Źródło:
    Journal of Telecommunications and Information Technology; 2022, 1; 79--92
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effectiveness of the spatial acceleration modulus for rolling elements bearing fault detection
    Autorzy:
    Cotogno, M.
    Cocconcelli, M.
    Rubini, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/329466.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    rolling element bearing
    diagnostic
    spatial acceleration modulus
    SAM
    SNR
    spectral Kurtosis
    envelope analysis
    Opis:
    Rolling Elements Bearing (REB) condition monitoring is mainly based on the analysis of acceleration (vibration) signal in the load direction. This is one of the three components of the acceleration vector in 3D space: the main idea of this paper is the recovery of additional fault information from the other two acceleration vector components by combining them to obtain the modulus of the spatial acceleration (SAM) vector. The REB diagnostic performances of the SAM are investigated and compared to the load direction of vibration by means a rough estimator of the “Signal-to-Noise” Ratio and the Spectral Kurtosis. The SAM provides a higher SNR than the single load direction. Finally, Spectral Kurtosis driven Envelope analysis is performed for further comparison of the two signals: its results highlight that demodulation of the SAM isn’t stricly necessary to extract the fault features, which are already available in the raw signal spectrum.
    Źródło:
    Diagnostyka; 2013, 14, 4; 27-34
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multipath detection with the combination of SNR measurements – Example from urban environment
    Autorzy:
    Špánik, P.
    Hefty, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/145370.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    satelita nawigacyjny
    fala radiowa
    pomiar szumu
    multipath
    detection
    SNR
    three-frequency combination
    GNSS positioning
    Opis:
    Multipath is one of the most severe station-dependent error sources in both static and kinematic positioning. Relatively new and simple detection technique using the Signal-to-Noise (SNR) measurements on three frequencies will be presented based on idea of Strode and Groves. Exploitation of SNR measurements is benefi cial especially for their unambiguous character. Method is based on the fact that SNR values are closely linked with estimation of pseudo-ranges and phase measurements during signal correlation processing. Due to this connection, combination of SNR values can be used to detect anomalous behavior in received signal, however some kind of calibration in low multipath environment has to be done previously. In case of multipath, phase measurements on different frequencies will not be affected in the same manner. Specular multipath, e.g. from building wall introduces additional path delay which is interpreted differently on each of the used carrier, due to different wavelengths. Experimental results of multipath detection in urban environment will be presented. Originally proposed method is designed to work with three different frequencies in each epoch, thus only utilization of GPS Block II-F and Galileo satellites is possible. Simplification of detection statistics to use only two frequencies is made and results using GPS and GLONASS systems are presented along with results obtained using original formula.
    Źródło:
    Geodesy and Cartography; 2017, 66, 2; 305-315
    2080-6736
    2300-2581
    Pojawia się w:
    Geodesy and Cartography
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance of Hybrid Sensing Method in Environment with Noise Uncertainty
    Autorzy:
    Kustra, M.
    Kosmowski, K.
    Suchański, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/308868.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    Covariance Absolute Value
    Cyclic Autocorrelation Function
    hybrid detector
    noise uncertainty
    OFDM
    SNR wall
    WiMAX
    Opis:
    The paper presents a novel hybrid spectrum sensing method used in cognitive radio and presents a hybrid detector (HD) which improves the sensing performance. The proposed HD takes advantage of the energy detection (ED) principle and a method based on Covariance Absolute Value (CAV), as well as on Cyclic Autocorrelation Function (CAF). The paper shows the limitations of using ED, resulting from the uncertainty of spectral density of noise power estimation, known as the SNR wall. The paper describes a system model and presents simulation results for the OFDM signal of a WiMAX-based communications system. The simulation results refer to an ideal environment with well-known parameters, and to an environment with uncertain spectral density of noise power estimation.
    Źródło:
    Journal of Telecommunications and Information Technology; 2018, 1; 51-57
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Identification of advanced optical modulation format and estimation of signal-to-noise-ratio based on parallel-twin convolutional neural network
    Autorzy:
    Dong, Xiaowei
    Yu, Zhihui
    Powiązania:
    https://bibliotekanauki.pl/articles/27310103.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    deep learning
    PT-CNN
    parallel-twin convolutional neural network
    constellation diagram
    modulation format identification
    SNR estimation
    Opis:
    In this paper, we design a parallel-twin convolutional neural network (PT-CNN) deep learning model and use the signal constellation diagram to realize the identification of six advanced optical modulation formats (QPSK, 4QAM, 8PSK, 8QAM, 16PSK, 16QAM) and signal-to-noise-ratio (SNR) estimation. The influence of PT-CNN with different layers and kernel sizes is investigated and the optimal network model is chosen. Simulation results demonstrate that the proposed method has the advantages of not requiring manual feature extraction, having the ability to clearly distinguish the six modulation formats with 100% accuracy when SNR of the received signal sequences is higher than 12 dB. In addition, the high-accurate SNR estimation is realized simultaneously without increasing additional system complexity.
    Źródło:
    Optica Applicata; 2023, 53, 2; 281--289
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wykorzystanie zmodernizowanej aparatury oblotu technicznego zainstalowanej na samolocie SONEX LL do oblotu stacji naprowadzania rakiet systemu NEWA
    Use of modernized flight test equipment onboard of SONEX LL aircraft to fly the Newa Missile Guidance System
    Autorzy:
    Karczmarz, Dariusz
    Mądrzycki, Przemysław
    Szkudlarz, Henryk
    Grzywiński, Stanisław
    Podciechowski, Maciej
    Żygadło, Stanisław
    Powiązania:
    https://bibliotekanauki.pl/articles/38943397.pdf
    Data publikacji:
    2023
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    aparatura
    oblot techniczny
    stacja naprowadzania rakiet
    kontrola parametrów technicznych
    SNR
    technical flight
    equipment
    missile guidance station
    control of technical parameters
    Opis:
    W artykule omówiono modernizację aparatury do przeprowadzania oblotów technicznych Przeciwlotniczego Zestawu Rakietowego NEWA SC (SA-3 Goa – kod NATO) polegającą na zastąpieniu samolotu TS-11 Iskra samolotem SONEX LL oraz przystoso-waniu zestawu aparatury oblotowej montowanej dotychczas na TS-11 Iskra do nowego samolotu-nosiciela. Przeprowadzono badania porównawcze w warunkach poligonowych, które potwierdziły poprawność przyjętych rozwiązań technicznych.
    The article discusses the modernization of the Anti-Aircraft Missile System NEWA SC (SA-3 Goa – NATO code) flight test equipment, consisting in replacing the TS-11 Iskra aircraft with the SONEX LL aircraft and adapting the set of flight test equipment previously mounted on the TS-11 Iskra to the new carrier aircraft. Comparative tests were carried out in field conditions, which confirmed the correctness of the adopted technical solutions.
    Źródło:
    Journal of KONBiN; 2023, 53, 4; 61-78
    1895-8281
    2083-4608
    Pojawia się w:
    Journal of KONBiN
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Inclusive Performance Analysis of Single-branch Single-relay AF Transmission in a Mixed Rayleigh-Nakagami-m Fading Environment
    Autorzy:
    Benmahmoud, Slimane
    Powiązania:
    https://bibliotekanauki.pl/articles/307994.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    amplify-and-forward (AF)
    decode-and-forward (DF)
    two/dual-hop relaying
    outage probability
    ergodic capacity
    signal-to-noise ratio (SNR)
    Opis:
    In this paper, the end-to-end performance of a single-branch two-hop amplify-and-forward (AF) relaying network in a mixed Rayleigh-Nakagami-m fading environment, is investigated. Four different fading scenarios and three standard relay configurations for each scenario are considered. Exact analytical expressions for the outage probability and tight upper bounds for the ergodic capacity are derived. Results of Monte Carlo simulations are provided to verify the accuracy of the analytical results.
    Źródło:
    Journal of Telecommunications and Information Technology; 2019, 3; 39-48
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    ANSDM converters dynamic range design process
    Autorzy:
    Golański, Ryszard
    Godek, Juliusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1402376.pdf
    Data publikacji:
    2020
    Wydawca:
    Państwowa Wyższa Szkoła Zawodowa w Tarnowie
    Tematy:
    delta modulation
    non-uniform sampling
    SNR
    dynamic range
    Lambert W function
    sampling interval
    Maple
    modulacja delta
    nierównomierne próbkowanie
    zakres dynamiczny
    funkcja Lamberta
    odstęp próbkowania
    Opis:
    The results of analytic and simulating works proved that for nonstationary sources, the delta converters with adaptive sampling expose higher coding efficiency than the former proposals, based on uniform sampling methods. The knowledge of the sampling interval range and the algorithm of the Nonuniform Sampling Delta Modulation and Adaptive Nonuniform Sampling Delta Modulation allows finding the necessary number of the sampling intervals and their values that maximizes SNR. The total dynamic range of the ANSDM modulator is the product of the dynamic range both from sampling interval and step size adaptation. Due to the high complexity of the calculations, the ANSDMsoft program was developed to support computing. All computational works were carried out using the Maple environment. Maple allows to solve complex mathematical functions and display their results in a simple way. Most importantly, it supports the LambertW function, used in the computing of NSDM or ANSDM modulators parameters. Graphic illustrations of the NSDM and ANSDM modulator dynamic range as a function of the minimum and maximum sampling frequency are presented.
    Źródło:
    Science, Technology and Innovation; 2020, 10, 3; 1-7
    2544-9125
    Pojawia się w:
    Science, Technology and Innovation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stacja referencyjna w Hornsundzie (Spitsbergen) : wybór lokalizacji, perspektywy rozbudowy i wykorzystanie
    A reference station in Hornsund (Spitsbergen) : determination of its location, future development, and usage
    Autorzy:
    Węzka, K.
    Paśnikowski, M.
    Walo, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/210815.pdf
    Data publikacji:
    2010
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    geodezja i kartografia
    geodezja satelitarna
    stacja referencyjna
    IGS
    wielodrożność sygnału
    pomiary GNSS na dużych szerokościach geograficznych
    geodesy and cartography
    satellite geodesy
    reference station
    multipath effect
    SNR
    GNSS measurements at high latitudes
    Opis:
    Głównym celem projektu realizowanego podczas wyprawy na Spitsbergen w 2008 roku była analiza funkcjonowania stacji referencyjnej w Hornsundzie, w celu wyboru jej odpowiedniej lokalizacji. W 2005 roku podczas wyprawy studentów i pracowników Wydziału Geodezji i Kartografii na Spitsbergen w fiordzie Hornsund została uruchomiona stacja referencyjna. Analiza obserwacji zgromadzonych na stacji w pierwszym okresie jej pracy wykazała znaczny efekt wielodrożności sygnału. Efekt ten okazał się na tyle duży, że zdecydowano o przeniesieniu anteny w inne miejsce. Jednak z uwagi na trwającą rozbudowę bazy, zmianę lokalizacji anteny zaplanowano dopiero po skończeniu prac remontowo-budowlanych. Podczas wyprawy w 2008 roku wybrano zatem docelową lokalizację spełniającą warunki prawidłowego ustawienia anteny stacji referencyjnej. Wykonano także serię dwunastu dobowych obserwacji testowych, które pozwoliły na wstępne wyznaczenie pozycji stacji oraz analizę jakości sygnałów GNSS. Praca prezentuje analizę porównawczą obserwacji zgromadzonych w starej i nowej lokalizacji anteny oraz zawiera opis otoczenia i jego wpływ na błędy wielodrożności sygnału. Autorzy przedstawiają ponadto przykład wykorzystania stacji referencyjnej w Hornsundzie oraz planowaną koncepcję rozbudowy systemu stacji referencyjnych dookoła Spitsbergenu.
    Determination of a new proper location of the reference station based upon the analysis of the existing point was the main aim of the project which was conducted during the expedition to Spitsbergen in 2008. The existing reference station in the Hornsud Fjord was activated during the expedition in 2005 by the students and research workers of the Faculty of Geodesy and Cartography. The analysis of the observation gathered during the first period of the station's activity demonstrated significant multipath effect, which appearance occurred high enough to force the change of the location of the reference station. Because of the modernization of the polar station where the reference point is located, the determination of the new location of the antenna had to start after finishing the building works. Therefore during the expedition in 2008, the final location of the reference station, where conditions comply with the requirements, was chosen. Additionally, a series of twelve 24-hour long measurements were conducted, which allowed to determine the position of the new station and to analyze the quality of the GPS signal. This paper presents the comparative analysis of the observation collected in two locations of the station. It also contains the description of the surrounding environment and its influence on the multipath effect. Furthermore, the authors present the possibilities of usage of the reference station in Hornsud and deliver the concept of developing a system of the reference points around Spitsbergen.
    Źródło:
    Biuletyn Wojskowej Akademii Technicznej; 2010, 59, 2; 179-195
    1234-5865
    Pojawia się w:
    Biuletyn Wojskowej Akademii Technicznej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of SHIFTZCC codes for Optical CDMA system
    Autorzy:
    Panda, Satyasen
    Powiązania:
    https://bibliotekanauki.pl/articles/1178705.pdf
    Data publikacji:
    2017
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    cross correlation (CC)
    multiple access interference (MAI)
    optical code division multiple access (OCDMA)
    shift zero cross correlation code (SHIFTZCC) and signal to noise ratio (SNR)
    spectral amplitude coding optical code division multiple access (SAC-OCDMA)
    Opis:
    In this paper, we propose a novel SAC-OCDMA code called Shift Zero Cross Correlation (SHIFTZCC) code with zero cross correlation property to minimize the Multiple Access Interface (MAI), to be more scalable and secure compared to the other existing SAC-OCDMA codes. This SHIFTZCC code is constructed using address segment and data segment. In this work, the proposed SHIFTZCC code is implemented in an optical network using the Opti-System software for the spectral amplitude coded optical code division multiple access (SAC-OCDMA) scheme. The chief advantage of the proposed SHIFTZCC code is the zero cross correlation property, which reduces both the MAI and other noises improving the system performance. The proposed SHIFTZCC code provides flexibility in selecting the code parameters, supports a large number of users with higher data rate and longer fiber length. Simulation results prove that the optical code division multiple access system based on the proposed SHIFTZCC code supports maximum number of simultaneous users with higher transmission rate, lower bit error rates (BER) and longer travelling distance without any signal quality degradation, as compared to the former existing SAC-OCDMA codes.
    Źródło:
    World Scientific News; 2017, 67, 2; 365-389
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sampling Jitter in Audio A/D Converters
    Autorzy:
    Kulka, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/177046.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    analog-to-digital converter
    ADC
    successive approximation register (SAR)
    sigma-delta ADC
    sample-and-hold circuit
    DT sigma delta modulator
    CT sigma delta modulator
    time jitter
    aperture jitter
    clock jitter
    periodic clock jitter
    signal-to-noise ratio (SNR)
    Opis:
    This paper provides an overview of the effects of timing jitter in audio sampling analog-to-digital converters (ADCs), i.e. PCM (conventional or Nyquist sampling) ADCs and sigma-delta (ΣΔ) ADCs. Jitter in a digital audio is often defined as short- term fluctuations of the sampling instants of a digital signal from their ideal positions in time. The influence of the jitter increases particularly with the improvements in both resolution and sampling rate of today’s audio ADCs. At higher frequencies of the input signals the sampling jitter becomes a dominant factor in limiting the ADCs performance in terms of signal-to-noise ratio (SNR) and dynamic range (DR).
    Źródło:
    Archives of Acoustics; 2011, 36, 4; 831-849
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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