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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
Wyświetlanie 1-15 z 26

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