Relevant bibliographies by topics / Signal energy spectrum

Academic literature on the topic 'Signal energy spectrum'

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Published: 30 May 2022
Last updated: 31 May 2022

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Journal articles on the topic "Signal energy spectrum"

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Fang, Yuan, Lixiang Li, Yixiao Li, Haipeng Peng, and Yixian Yang. "Low Energy Consumption Compressed Spectrum Sensing Based on Channel Energy Reconstruction in Cognitive Radio Network." Sensors 20, no. 5 (February 26, 2020): 1264. http://dx.doi.org/10.3390/s20051264.

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For wireless communication networks, cognitive radio (CR) can be used to obtain the available spectrum, and wideband compressed sensing plays a vital role in cognitive radio networks (CRNs). Using compressed sensing (CS), sampling and compression of the spectrum signal can be simultaneously achieved, and the original signal can be accurately recovered from the sampling data under sub-Nyquist rate. Using a set of wideband random filters to measure the channel energy, only the recovery of the channel energy is necessary, rather than that of all the original channel signals. Based on the semi-tensor product, this paper proposes a new model to achieve the energy compression and reconstruction of spectral signals, called semi-tensor product compressed spectrum sensing (STP-CSS), which is a generalization of traditional spectrum sensing. The experimental results show that STP-CSS can flexibly generate a low-dimensional sensing matrix for energy compression and parallel reconstruction of the signal. Compared with the existing methods, STP-CSS is proved to effectively reduce the calculation complexity of sensor nodes. Hence, the proposed model markedly improves the spectrum sensing speed of network nodes and saves storage space and energy consumption.
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Liu, Mingxin, Wei Xue, Peisong Jia, Sergey B. Makarov, and Beiming Li. "Research on Spectrum Optimization Technology for a Wireless Communication System." Symmetry 12, no. 1 (December 23, 2019): 34. http://dx.doi.org/10.3390/sym12010034.

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In this study, the principle of minimum spectral energy leakage is applied, and the mathematical model is also established by the general function through adding different constraints. To allow the target baseband signal to have a high-quality time-domain representation, it is assumed that the baseband signal is an even function. The time-domain waveform has symmetry about the y-axis, and the objective function is obtained by Fourier series approximation. The frequency-domain characteristics of the baseband signals are obtained by adding the energy limitation condition and the boundary restriction condition. Limit a point at the appropriate position of the main lobe of the normalized energy spectral density function, and at the same time, limit the appropriate point at the first side lobe. The changes of the points modified the whole characteristic of the frequency-domain. To more conveniently compare the characteristics of the signal under different constraints, according to the symmetry of the frequency-domain of the signal, the normalized energy spectrum main lobe energy ratio is defined as a parameter, and thereby the spectral performance of the signal is discriminated by the size of this parameter. Through comparative analysis, the signal with the frequency-domain restriction conditions added has a larger normalized energy spectrum main lobe energy ratio. With increasing roll-off factor n, the energy ratio of the main energy spectrum of the normalized spectrum increases accordingly, i.e., the energy leakage is effectively suppressed. The baseband signal can be considered more suitable as a modern wireless communication system and can be obtained by adding a suitable restriction condition and establishing a model with a general function.
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Hu, Wei Bing, Wei Hu, and Yu Zheng. "Wavelet Analysis in Damage Detection for Bridge Structure." Key Engineering Materials 417-418 (October 2009): 813–16. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.813.

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The damage of structure leads to variation of structural modal parameter，so the wavelet transform for damage detection is introduced in this paper for considering the variation. First, structural dynamic response signal on the basis of the vibration-based structural damage diagnosis methods is calculated by structural analysis in the paper, then, each of sub-signals is calculated according to wavelet analysis, also, the sub-signal energy spectrum of dynamic response signal and energy spectrum variation are known. By observing the difference of the sub-signal and the variation of the sub-signal energy spectrum, we can get the variation of structural modal parameter and the sub-signal energy spectrum due to the performance degradation of the whole structure and local variations of damage level and location ,so that this method can be used in on-line damage detection for bridge structure.
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Wang, Feng Li, and Hui Xing. "An Investigation of Tooth Wear Diagnosis of Gear Based on Process Systems Modeling." Advanced Materials Research 549 (July 2012): 834–38. http://dx.doi.org/10.4028/www.scientific.net/amr.549.834.

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Targeting the advantages of local wave analysis(LWA) and the characteristics of gear fault vibration signals, LWA is introduced into gear fault diagnosis. The concept of the instantaneous energy in time- frequency analysis, based on local wave time-frequency spectrum, was used to measure the energy distribution of the signal in time-frequency domain. Furthermore, when tooth wear occurs in gear, the energy of the gear vibration signal would change correspondingly, whilst local wave time-frequency spectrum can exactly provide the instantaneous energy distribution of the signal with the change of the time and frequency. Thus, the fault information of the gear vibration signal can be extracted effectively from the local wave time-frequency spectrum. The analysis results from the experimental signals show that local wave time-frequency analysis could extract the characteristics information of the gear fault vibration signal effectively.
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Et.al, Tae-Yun Jung. "Spectrum Sensing Based On Deep Learning To Increase Spectrum Utilization." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 6 (April 10, 2021): 538–43. http://dx.doi.org/10.17762/turcomat.v12i6.1971.

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This paper proposes a new spectrum sensing technique for cognitive radio systems. To determine vacancy of the spectrum, the proposed method employs the recurrent neural network (RNN), one of the popular deep learning techniques. The proposed technique determines the spectrum occupancy of the primary user (PU) by observing the received signal’s energy and any information on the PU signal characteristic is not used. To this end, the received signal’s spectrum is obtained by fast Fourier transform (FFT). This process is performed on consecutive received signals and the resulting spectrums are stacked. Finally, a 2-dimensional spectrum (or spectrogram) is made. This 2-D spectrum is cut into sensing channel bandwidths and inputted to the deep learning model to decide the channel’s occupancy. While the recently published spectrum sensing technique based on convolutional neural network (CNN) relies on an empty channel, the proposed technique does not require any empty channel. Only the channel signal of interest to sense is needed. Since spectrum sensing results is two (busy or idle), binary classification deep learning model is developed. According to the computer simulation results, the proposed method has similar performance with the conventional CNN-based method while the spectral efficiency of the proposed method is much higher than that of the existing scheme. In addition, the overall learnable parameters of the proposed deep learning model is only 2/3 of the existing method
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Strelkovskaya, Irina, Irina Solovskaya, and Anastasiya Makoganiuk. "A Study of the Extremum of the Total Energy of the Selective Signals Constructed by Quadratic Splines." Periodica Polytechnica Electrical Engineering and Computer Science 63, no. 1 (December 20, 2018): 30–36. http://dx.doi.org/10.3311/ppee.12457.

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The development of mobile communication networks in the direction of 5G networks implies the use of the radio interface that is based on new signal-code structures, the choice of which will determine their further development and the ability of operators to provide innovative services. The use of quadratic splines for the synthesis of selective signals with a finite spectrum, free from intersymbol interference, is proposed. An analytical expression for the synthesized signal in the time and frequency domains is obtained. A study was made of the dependence of the total energy of a selective signal on the parameters of a quadratic spline, which is used to interpolate the spectral density in the transition region using the methods of differential calculus of functions of several variables. To study the extremum of the total energy of a selective signal, the parameters of the width of the transition area α was used and the coefficient of rounding the spectrum ρ, the variation of whose spectral density allowed us to establish the limits of the change in the total energy of the signal in question. Conducted studies allow us to synthesize the signal and formulate recommendations on how by changing the parameters of the signal, you can get a signal with the desired properties. This will allow to obtain the optimal waveform in accordance with the selected criteria, providing for the required energy performance of the signal in the radio interface of 5G networks.
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Xu, Hui Bin, and Kui Zhang. "The UWB Signals of Power Spectral Density." Advanced Materials Research 472-475 (February 2012): 2748–51. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.2748.

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System or the waveform is energy, or has the power value. Generally, periodic signal and random signal is power signal,while the determine nonperiodic signal is energy signal. For the energy signal,we can use the energy spectrum density to describe the signal on the energy unit bandwidth,the unit is the joule/Hertz.For the power signal,we can use the power spectral density to describe the signal on the energy unit bandwidth,the unit for w/Hertz.
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Li, Linna, and Yue You. "Time-frequency energy analysis of deepwater explosion shock wave signals based on HHT." MATEC Web of Conferences 336 (2021): 01017. http://dx.doi.org/10.1051/matecconf/202133601017.

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In order to study the time-frequency characteristics of shock wave signals under deep water explosion conditions, experiments are performed using water medium explosion containers to simulate different water depth conditions, and signal analysis is performed on the shock wave data obtained in the experiments. Traditional time-frequency analysis methods such as Fourier transform and wavelet transform have many limitations on deep-water explosion shock wave signal analysis, the HHT method is used to analyse the experimental data from the three-dimensional Hilbert spectrum, marginal spectrum and instantaneous energy spectrum. The results show that the time-frequency method can effectively extract the frequency components of the deep-water explosion load signal in different periods. It provides a reference for people to understand the time frequency characteristics of shock wave signals in deep water.
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Liu, Yao Lin, Feng Han, Zhen Liu, and Min Chen Zhai. "Analysis of Energy Loss-Gain Error in Discrete Fourier Transform." Applied Mechanics and Materials 568-570 (June 2014): 172–75. http://dx.doi.org/10.4028/www.scientific.net/amm.568-570.172.

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In asynchronous sampling, discrete Fourier transform (DFT) spectrum involves errors. Scholars have done great investigations on the correction techniques of DFT spectrum, but the errors have not been completely eliminated all along. In this paper, spectrums were examined from the principle of conservation of energy. It is unnoticed before that the energy of the digital signal, which is the analysis object of DFT, isn't equal to that of the finite continuous signal truncated by rectangular window. Thus the energy of their spectrums are different according to the Parseval's theorem. The Energy Loss-Gain (ELG) error was introduced to express the energy difference between these two spectrums. The ELG error is zero if the observed continuous signal is truncated in integral multiple of half cycle and it is related to the cycle number and sampling number in one cycle. Analysis show that the ELG error decreases with the increment of these two parameters, which are helpful to the engineering.
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Zhai, Juan, Jiehao Chen, Hongjian Lin, Jinge Zhou, and Jinchu Huang. "Development of a Nuclear Energy Spectrum Signal Generator." Journal of Physics: Conference Series 1739 (January 2021): 012017. http://dx.doi.org/10.1088/1742-6596/1739/1/012017.

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Dissertations / Theses on the topic "Signal energy spectrum"

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Qu, Yang. "Mixed Signal Detection, Estimation, and Modulation Classification." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1576615989584971.

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López, Benítez Miguel. "Spectrum usage models for the analysis, design and simulation of cognitive radio networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2011. http://hdl.handle.net/10803/33282.

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The owned spectrum allocation policy, in use since the early days of modern radio communications, has been proven to effectively control interference among radio communication systems. However, the overwhelming proliferation of new operators, innovative services and wireless technologies during the last years has resulted, under this static regulatory regime, in the depletion of spectrum bands with commercially attractive radio propagation characteristics. An important number of spectrum measurements, however, have shown that spectrum is mostly underutilized, thus indicating that the virtual spectrum scarcity problem actually results from static and inflexible spectrum management policies rather than the physical scarcity of radio resources. This situation has motivated the emergence of Dynamic Spectrum Access (DSA) methods based on the Cognitive Radio (CR) paradigm, which has gained popularity as a promising solution to conciliate the existing conflicts between spectrum demand growth and spectrum underutilization. The basic underlying idea of DSA/CR is to allow unlicensed (secondary) users to access in an opportunistic and non-interfering manner some licensed bands temporarily unoccupied by the licensed (primary) users. Due to the opportunistic nature of this principle, the behavior and performance of a DSA/CR network depends on the spectrum occupancy patterns of the primary system. A realistic and accurate modeling of such patterns becomes therefore essential and extremely useful in the domain of DSA/CR research. The potential applicability of spectrum usage models ranges from analytical studies to the design and dimensioning of secondary networks as well as the development of innovative simulation tools and more efficient DSA/CR techniques. Spectrum occupancy modeling in the context of DSA/CR constitutes a rather unexplored research area. This dissertation addresses the problem of modeling spectrum usage in the context of DSA/CR by contributing a comprehensive and holistic set of realistic models capable to accurately capture and reproduce the statistical properties of spectrum usage in real radio communication systems in the time, frequency and space dimensions. The first part of this dissertation addresses the development of a unified methodological framework for spectrum measurements in the context of DSA/CR and presents the results of an extensive spectrum measurement campaign performed over a wide variety of locations and scenarios in the metropolitan area of Barcelona, Spain, to identify potential bands of interest for future DSA/CR deployments. To the best of the author's knowledge, this is the first study of these characteristics performed under the scope of the Spanish spectrum regulation and one of the earliest studies in Europe. The second part deals with various specific aspects related to the processing of measurements to extract spectrum occupancy patterns, which is largely similar to the problem of spectrum sensing in DSA/CR. The performance of energy detection, the most widely employed spectrum sensing technique in DSA/CR, is first assessed empirically. The outcome of this study motivates the development of a more accurate theoretical-empirical performance model as well as an improved energy detection scheme capable to outperform the conventional method while preserving a similar level of complexity, computational cost and application. The findings of these studies are finally applied in the third part of the dissertation to the development of innovative spectrum usage models for the time (in discrete- and continuous-time versions), frequency and space domains. The proposed models can been combined and integrated into a unified modeling approach where the time, frequency and space dimensions of spectrum usage can simultaneously be reproduced, thus providing a complete and holistic characterization of spectrum usage in real systems for the analysis, design and simulation of the future DSA/CR networks.
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Zapletal, Ondřej. "Moderní kódování řečového signálu pomocí přeparametrizovaných modelů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218550.

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The theoretical contents of this thesis are studies of overcomplete models. Those are the models of signals, on which is set for their parametrization more variables, than it's necessary and consequently there's computed so-called sparse solution via iteration algorithms. A goal of this analysis is a selection just of the considerable (sparse) parameters. The theory is based on a linear algebra, vector spaces, bases and so-called frames. The task of the individual project of this thesis is a description and simulation of two speech coders: a classical coder based on linear predictive speech coding and a coder, that's making use of overcomplete stochastic ARMA processes models. A part of their realization is to simulate their decoders and a analyze their reconstruction quality. For their realization there is used MATLAB and an overcomplete models' library (toolbox frames).
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Ainomäe, Ahti. "Distributed Detection in Cognitive Radio Networks." Licentiate thesis, KTH, Teknisk informationsvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213957.

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One of the problems with the modern radio communication is the lack of availableradio frequencies. Recent studies have shown that, while the available licensed radiospectrum becomes more occupied, the assigned spectrum is significantly underutilized.To alleviate the situation, cognitive radio (CR) technology has been proposedto provide an opportunistic access to the licensed spectrum areas. Secondary CRsystems need to cyclically detect the presence of a primary user by continuouslysensing the spectrum area of interest. Radiowave propagation effects like fading andshadowing often complicate sensing of spectrum holes. When spectrum sensing isperformed in a cooperative manner, then the resulting sensing performance can beimproved and stabilized. In this thesis, two fully distributed and adaptive cooperative Primary User (PU)detection solutions for CR networks are studied. In the first part of this thesis we study a distributed energy detection schemewithout using any fusion center. Due to reduced communication such a topologyis more energy efficient. We propose the usage of distributed, diffusion least meansquare (LMS) type of power estimation algorithms with different network topologies.We analyze the resulting energy detection performance by using a commonframework and verify the theoretical findings through simulations. In the second part of this thesis we propose a fully distributed detection scheme,based on the largest eigenvalue of adaptively estimated correlation matrices, assumingthat the primary user signal is temporally correlated. Different forms of diffusionLMS algorithms are used for estimating and averaging the correlation matrices overthe CR network. The resulting detection performance is analyzed using a commonframework. In order to obtain analytic results on the detection performance, theadaptive correlation matrix estimates are approximated by a Wishart distribution.The theoretical findings are verified through simulations.

QC 20170908

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Khalaf, Ziad. "Contributions à l'étude de détection des bandes libres dans le contexte de la radio intelligente." Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00812666.

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Les systèmes de communications sans fil ne cessent de se multiplier pour devenir incontournables de nos jours. Cette croissance cause une augmentation de la demande des ressources spectrales, qui sont devenues de plus en plus rares. Afin de résoudre ce problème de pénurie de fréquences, Joseph Mitola III, en 2000, a introduit l'idée de l'allocation dynamique du spectre. Il définit ainsi le terme " Cognitive Radio " (Radio Intelligente), qui est largement pressenti pour être le prochain Big Bang dans les futures communications sans fil [1]. Dans le cadre de ce travail on s'intéresse à la problématique du spectrum sensing qui est la détection de présence des Utilisateurs Primaires dans un spectre sous licence, dans le contexte de la radio intelligente. L'objectif de ce travail est de proposer des méthodes de détection efficaces à faible complexité et/ou à faible temps d'observation et ceci en utilisant le minimum d'information a priori sur le signal à détecter. Dans la première partie on traite le problème de détection d'un signal aléatoire dans le bruit. Deux grandes méthodes de détection sont utilisées : la détection d'énergie ou radiomètre et la détection cyclostationnaire. Dans notre contexte, ces méthodes sont plus complémentaires que concurrentes. Nous proposons une architecture hybride de détection des bandes libres, qui combine la simplicité du radiomètre et la robustesse des détecteurs cyclostationnaires. Deux méthodes de détection sont proposées qui se basent sur cette même architecture. Grâce au caractère adaptatif de l'architecture, la détection évolue au cours du temps pour tendre vers la complexité du détecteur d'énergie avec des performances proches du détecteur cyclostationnaire ou du radiomètre selon la méthode utilisée et l'environnement de travail. Dans un second temps on exploite la propriété parcimonieuse de la Fonction d'Autocorrelation Cyclique (FAC) pour proposer un nouvel estimateur aveugle qui se base sur le compressed sensing afin d'estimer le Vecteur d'Autocorrelation Cyclique (VAC), qui est un vecteur particulier de la Fonction d'Autocorrelation Cyclique pour un délai fixe. On montre par simulation que ce nouvel estimateur donne de meilleures performances que celles obtenues avec l'estimateur classique, qui est non aveugle et ceci dans les mêmes conditions et en utilisant le même nombre d'échantillons. On utilise l'estimateur proposé, pour proposer deux détecteurs aveugles utilisant moins d'échantillons que nécessite le détecteur temporel de second ordre de [2] qui se base sur l'estimateur classique de la FAC. Le premier détecteur exploite uniquement la propriété de parcimonie du VAC tandis que le second détecteur exploite en plus de la parcimonie la propriété de symétrie du VAC, lui permettant ainsi d'obtenir de meilleures performances. Ces deux détecteurs outre qu'ils sont aveugles sont plus performants que le détecteur non aveugle de [2] dans le cas d'un faible nombre d'échantillons.
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Muto, Shunsuke, and Yusuke Sasano. "Energy-drift correction of electron energy-loss spectra from prolonged data accumulation of low SNR signals." Oxford University Press, 2008. http://hdl.handle.net/2237/20779.

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Gianto, Gianto. "Multi-dimensional Teager-Kaiser signal processing for improved characterization using white light interferometry." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD026/document.

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L'utilisation de franges d'interférence en lumière blanche comme une sonde optique en microscopie interférométrique est d'une importance croissante dans la caractérisation des matériaux, la métrologie de surface et de l'imagerie médicale. L'Interférométrie en lumière blanche est une technique basée sur la détection de l'enveloppe de franges d'interférence. Il a été démontré antérieurement, la capacité des approches 2D à rivaliser avec certaines méthodes classiques utilisées dans le domaine de l'interférométrie, en termes de robustesse et de temps de calcul. En outre, alors que la plupart des méthodes tiennent compte seulement des données 1 D, il semblerait avantageux de prendre en compte le voisinage spatial utilisant des approches multidimensionnelles (2D/3D), y compris le paramètre de temps afin d'améliorer les mesures. Le but de ce projet de thèse est de développer de nouvelles approches n-D qui sont appropriées pour une meilleure caractérisation des surfaces plus complexes et des couches transparentes
The use of white light interference fringes as an optical probe in microscopy is of growing importance in materials characterization, surface metrology and medical imaging. Coherence Scanning Interferometry (CSI, also known as White Light Scanning Interferometry, WSLI) is well known for surface roughness and topology measurement [1]. Full-Field Optical Coherence Tomography (FF-OCT) is the version used for the tomographic analysis of complex transparent layers. Both techniques generally make use of some sort of fringe scanning along the optical axis and the acquisition of a stack of xyz images. Image processing is then used to identify the fringe envelopes along z at each pixel in order to measure the positions of either a single surface or of multiple scattering objects within a layer.In CSI, the measurement of surface shape generally requires peak or phase extraction of the mono dimensional fringe signal. Most of the methods are based on an AM-FM signal model, which represents the variation in light intensity measured along the optical axis of an interference microscope [2]. We have demonstrated earlier [3, 4] the ability of 2D approaches to compete with some classical methods used in the field of interferometry, in terms of robustness and computing time. In addition, whereas most methods only take into account the 1D data, it would seem advantageous to take into account the spatial neighborhood using multidimensional approaches (2D, 3D, 4D), including the time parameter in order to improve the measurements.The purpose of this PhD project is to develop new n-D approaches that are suitable for improved characterization of more complex surfaces and transparent layers. In addition, we will enrich the field of study by means of heterogeneous image processing from multiple sensor sources (heterogeneous data fusion). Applications considered will be in the fields of materials metrology, biomaterials and medical imaging
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Ferreira, Rafael Jales Lima. "Proposta e avaliação de uma arquitetura ROADM para sistemas de transmissão O-OFDM." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18155/tde-25092018-155110/.

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Este trabalho tem como cenário as redes ópticas de próxima geração, por onde trafegarão supercanais flexíveis, sincronizados e modulados a taxas variáveis que podem chegar à ordem de Terabit por segundo. Mais especificamente, focaliza o supercanal óptico gerado a partir de um único laser (laser semente) composto por portadoras ortogonais entre si, travadas em frequência e moduladas de maneira síncrona. Tal arranjo constitui um sistema de transmissão conhecido como OFDM óptico (optical orthogonal frequency division multiplexing, O-OFDM). Este esquema não requer banda de guarda entre canais, o que proporciona uma melhor eficiência espectral, se mantidas as condições de ortogonalidade mútua, quando comparado à técnica Nyquist WDM (Nyquist wavelength division multiplexing, N-WDM), usualmente reconhecida como base para os sistemas de próxima geração. Muitos são os desafios a serem vencidos antes que a técnica O-OFDM possa ser efetivamente implantada comercialmente e esta tese busca, através de um estudo de seus princípios de funcionamento e módulos constituintes, elencar os principais obstáculos e as possíveis maneira de superá-los. Sem pretender ser exaustivo em termos de tecnologias disponíveis para alcançar este fim, o objetivo é propor novas configurações de subsistemas e arquitetura de nó para o transmissor, o nó intermediário e o receptor coerente, capazes de executar, de forma relativamente simples no domínio óptico, as principais funcionalidades de uma transmissão ponto a ponto com nós deriva/insere intermediários. Através de simulações sistêmicas e demonstrações experimentais, como prova de conceito, dois cenários são abordados: análise do desempenho numa transmissão ponto a ponto, e operação em rede, com derivação e inserção de canal em nós intermediários. Ao final, através de uma análise qualitativa, é feita uma estimativa de componentes e subsistemas necessários para tornar a transmissão de sinais O-OFDM implementável por tecnologias de fotônica integrada que atenda, com eficiência espectral e economia de energia, a sempre crescente demanda de capacidade em sistemas de transmissão óptica.
This work focuses on the scenario of next generation optical networking, where flexible optical superchannels will propagate modulated at variable rates that can reach terabits per second. More specifically, it focuses on the optical superchannel generated from a single laser (seed laser) composed of orthogonal carriers, which are frequency-locked and synchronously modulated. Such arrangement constitutes a transmission system known as optical orthogonal frequency division multiplexing (O-OFDM). This scheme does not require guard band between channels, which provides a better spectral efficiency, if the conditions of mutual orthogonality are maintained, when compared to the Nyquist wavelength dividing multiplexing (N-WDM) technique, usually recognized as the basis for the next generation systems. There are many challenges to overcome before O-OFDM technique can be effectively deployed commercially and this thesis seeks, through a study of its operating principles and constituent modules, to identify the main obstacles and the possible ways of overcoming them. Without intending to be exhaustive in terms of available technologies to achieve this aim, the objective is to propose new configurations of subsystems and node architecture for the transmitter, the intermediate node and the coherent receiver, able to perform in the optical domain, in a relatively simple way, the main features a point-to-point transmission with nodes drifting/inserting intermediates. Through systemic simulations and some experimental demonstrations, as proof of concept, two scenarios are addressed: performance analysis in a point-to-point transmission, and network operation, with channel derivation and insertion at intermediate nodes. At the end, through a qualitative analysis, an estimate of components and subsystems is made to make the transmission of O-OFDM signals implementable by integrated photonics technologies that meet, with spectral efficiency and energy savings, the ever increasing capacity demand in optical transmission systems.
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Bouchaala, Dhouha. "Investigation of Current Excitation for Personal Health and Biological Tissues Monitoring." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-204801.

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Bioimpedance spectroscopy is very useful in biomedical field as a safe and non-invasive technique. A stable and safe excitation current below than 0.5 mA for load impedances changing from 100 Ω to 10 kΩ in the full β-dispersion range from kHz up to 1 MHz is a big challenge for the design of the current source addressed by this thesis. For a good stability and high accuracy, the source should have a high output impedance. Different current source types in “current-mode approach” and “voltage-mode approach” were investigated and compared for usability in bioimpedance measurement systems. The “voltage-mode approach” with grounded load was proven to be more suitable and stable for biomedical measurements. Thereby the Tietze and the Howland circuit in dual configuration with negative feedback have shown the lowest error of the output current and the highest output impedance, where the improved Howland circuit in dual configuration with negative feedback is preferred because it has a simple structure, high accuracy and good stability. We suggest to improve the stability of the Howland circuit in dual configuration with negative feedback by introducing compensated operational amplifiers and to reduce stray capacitances at higher frequencies by adding gain compensation capacitor. We reach thereby an accuracy of 0.5% at low frequency and 0.9% at 1 MHz. With the realized accuracy of the designed voltage controlled current source, one decisive prerequisite for portable bioimpedance measurement system is achieved. In order to select the appropriate excitation signals for short measurement time, a comparative study of signals and their parameters was carried out. It leads to the selection of binary chirp signal as a suitable excitation signal due to its short measurement time about 100 μs, low crest factor lower than 2.8 and an energy efficiency higher than 54% in a very noisy signal. Simulation results show that the designed enhanced Howland current source excited by the binary chirp signal has low error and flatness in the whole range
Die Bioimpedanzspektroskopie gewinnt aufgrund ihrer besonderen Eigenschaften als nicht-invasive, schonende Messmethode zunehmend an Bedeutung im biomedizinischen Bereich. Dabei ergeben sich besondere erausforderungen für den Entwurf der Stromquelle zur Realisierung eines stabilen und sicheren Anregungsstroms. Gefordert ist eine hohe Genauigkeit bis zu einem Maximalstrom von 0.5 mA in einem Frequenzbereich, der der β-Dispersion entspricht, von wenigen kHz bis hin zu 1 MHz. Die Stabilität muss bei variablen Lastimpedanzen im Bereich von 100 Ω bis 10 kΩ gewährleistet sein. Dafür muss die Stromquelle eine hohe Ausgangsimpedanz aufweisen. Diese Arbeit fokussiert auf den Entwurf von spannungsgesteuerten Stromquellen. Verschiedene Arten von Stromquellen wurden untersucht und verglichen. Der "Voltage-Modus-Ansatz" mit Masse-referenzierter Last hat sich als besser geeignet und stabiler für biomedizinische Messungen erwiesen. Die Tietze-Schaltung und diese Howland-Schaltung zeigen dabei die niedrigsten Fehler des Ausgangsstroms und die höchste Ausgangsimpedanz. Im direkten Vergleich besitzt die verbesserte Howland-Schaltung doch eine einfachere Struktur, höhere Genauigkeit und bessere Stabilität und wird daher gegenüber der Tietze-Schaltung bevorzugt. Um weitere Stabilitätsverbesserungen bei der Howland-Schaltung zu erreichen, werden zwei Maβnahmen vorgeschlagen. Zum einen werden kompensierte Operationsverstärker eingeführt und zum anderen wird der Einfluss von Streukapazitäten bei hohen Frequenzen minimiert indem die Verstärkung mit Kondensatoren kompensiert wird. Durch diese Maβnahmen wird eine Genauigkeit von 0.5% bei niedrigen Frequenzen und 0.9% bei 1 MHz ermöglicht. Mit dem neuen Entwurf der spannungsgesteuerten Stromquelle ist ein entscheidender Meilenstein für die Realisierung tragbarer Messsysteme der Bioimpedanz erreicht. Um eine kurze Messzeit zu realisieren wurde eine vergleichende Studie von Anregungssignalen und deren Signalparameter durchgeführt. Die Ergebnisse zeigen, dass binäre Chirp-Signale aufgrund der reduzierten Messzeit, des niedrigen Crest-Faktors unter 2.8 und hohe Energieeffizienz von mehr als 54% bei hohem Rauschlevel besonders geeignet sind. Simulationsergebnisse zeigen, dass die entwickelte Howland-Stromquelle zusammen mit einem binären Mehrfrequenzsignal den geringsten Amplitudenfehler im gesamten Frequenzbereich realisiert
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Troublefield, Robert C. "DIGITAL RECEIVER PERFORMANCE." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606794.

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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
Bit errors often occur in a wireless communications link when impairments alter the transmitted signal. It is advantageous to be able to predict how well a system will tolerate transmission problems. This paper details laboratory performance measurements and comparisons in terms of evaluating configurations of a digital receiver for Feher patented Quadrature Phase Shift Keying (FQPSK-B) demodulation. The transmitted signal is subjected to calibrated levels of impairments while the receiver performance is monitored in real-time.
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Books on the topic "Signal energy spectrum"

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Berber, Stevan. Discrete Communication Systems. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198860792.001.0001.

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The book present essential theory and practice of the discrete communication systems design, based on the theory of discrete time stochastic processes, and their relation to the existing theory of digital communication systems. Using the notion of stochastic linear time invariant systems, in addition to the orhogonality principles, a general structure of the discrete communication system is constructed in terms of mathematical operators. Based on this structure, the MPSK, MFSK, QAM, OFDM and CDMA systems, using discrete modulation methods, are deduced as special cases. The signals are processed in the time and frequency domain, which requires precise derivatives of their amplitude spectral density functions, correlation functions and related energy and pover spectral densities. The book is self-sufficient, because it uses the unified notation both in the main ten chapters explaining communications systems theory and nine supplementary chapters dealing with the continuous and discrete time signal processing for both the deterministic and stochastic signals. In this context, the indexing of vital signals and finctions makes obvious distinction beteween them. Having in mind the controversial nature of the continuous time white Gaussian noise process, a separate chapter is dedicated to the noise discretisation by introducing notions of noise entropy and trauncated Gaussian density function to avoid limitations in applying the Nyquist criterion. The text of the book is acompained by the solutions of problems for all chapters and a set of deign projects with the defined projects’ topics and tasks and offered solutions.
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Wójcik-Gładysz, Anna. Ghrelin – hormone with many faces. Central regulation and therapy. The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 2020. http://dx.doi.org/10.22358/mono_awg_2020.

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Discovered in 1999, ghrelin, is one of the peptides co-creating the hypothalamicgastrointestinal axis, otherwise known as the brain-gut axis. Ghrelin participates in many physiological processes and spectrum of its activity is still being discovered. This 28 amino acid peptide ‒ a product of the ghrl gene, was found in all vertebrates and is synthesized and secreted mainly from enteroendocrine X/A cells located in the gastric mucosa of the stomach. Expression of the ghrelin receptor has been found in many nuclei of the hypothalamus involved in appetite regulation. Therefore it’s presumed that ghrelin is one of the crucial hormones deciphering the energy status required for the maintenance of organism homeostasis. Ghrelin acts as a signal of starvation or energy insufficiency and its level in plasma is reduced after the meal. Neuropeptide Y (NPY) and agouti-related peptide (AgRP; NPY/AgRP) neurons located in the arcuate nucleus (ARC) area are the main target of ghrelin in the hypothalamus. This subpopulation of neurons is indispensable for inducing orexigenic action of ghrelin. Moreover ghrelin acting as a neurohormone, mainly in the hypothalamus area, plays an important role in the regulation of growth and reproduction processes. Indeed, ghrelin action on reproductive processes has been observed in the systemic effects exerted at both hypothalamus-pituitary and gonadal levels. Similarly the GH-releasing ghrelin action was observed both on the hypothalamus level and directly on the somatotrophic cells in the pituitary and this dose-related GH releasing activity was found in in vitro as well as in in vivo experiments. In recent years, numerous studies revealed that ghrelin potentially takes part in the treatment of diseases associated with serious disturbances in the organism energy balance and/or functioning of the gastrointestinal tract. It was underlined that ghrelin may be a hormone with a broad spectrum of therapeutic effect on obesity and anorexia nervosa, as well as may also have protective effect on neurodegenerative diseases, inflammatory disorders or functional changes in the body caused by cancers. In overall, ghrelin treatment has been tested in over 100 preclinical studies with healthy volunteers as well as patients with various types of cancer, eating disorders such as anorexia nervosa and bulimia nervosa. It was observed that ghrelin has an excellent clinical safety profile and emerging side effects occurred only in 3–10% of patients and did not constitute a sufficient premise to discontinue the therapy. In general, it can be concluded that ghrelin may be sufficiently used as a prescription drug.
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Book chapters on the topic "Signal energy spectrum"

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Wang, Yun. "Estimating the Energy Spectrum of Cold Dark Matter Signal." In Unified Symmetry, 87–95. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1923-2_7.

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Mondal, Debanjan, Ruicheng Feng, Fengshou Gu, and Andrew D. Ball. "Reciprocating Compressor Fault Diagnosis Based on Airborne Acoustic Signal: Comparison Study Between Modulation Signal Bi-spectrum and Teager Energy Spectrum Method." In Proceedings of IncoME-V & CEPE Net-2020, 683–99. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75793-9_66.

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Wang, Xuemeng, Tao Peng, and Wenbo Wang. "Low-SNR Energy Detection Based on Relevance in Power Density Spectrum." In Proceedings of the 2015 International Conference on Communications, Signal Processing, and Systems, 283–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-49831-6_29.

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Du, Kaixuan, Xiaodi Han, and Lexin Yu. "A Scheme Against Spectrum Sensing Data Falsification Attacks Based on Improved Energy Detection Algorithm." In Proceedings of the 2015 International Conference on Communications, Signal Processing, and Systems, 423–30. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-49831-6_42.

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Mondal, Debanjan, Dong Zhen, Fengshou Gu, and Andrew D. Ball. "Fault Diagnosis of Reciprocating Compressor Using Empirical Mode Decomposition-Based Teager Energy Spectrum of Airborne Acoustic Signal." In Advances in Asset Management and Condition Monitoring, 939–52. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-57745-2_77.

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Nuzillard, Danielle, and Noël Bonnet. "BSS for Series of Electron Energy Loss Spectra." In Independent Component Analysis and Blind Signal Separation, 1150–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-30110-3_145.

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Henri, G. "Modelling the High Energy Spectra of AGN." In The Gamma Ray Sky with Compton GRO and SIGMA, 55–66. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0067-0_5.

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Ovsyannikova, Anna S., Sergey V. Zavjalov, Sergey B. Makarov, Sergey V. Volvenko, and Trinh Luong Quang. "Spectral and Energy Efficiency of Optimal Signals with Increased Duration, Providing Overcoming “Nyquist Barrier”." In Lecture Notes in Computer Science, 607–18. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-67380-6_57.

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Huang, Sen, Linna Li, Dongwang Zhong, Li He, and Jianfeng Si. "Vibration Signal Analysis of Chimney Blasting Based on HHT." In Advances in Transdisciplinary Engineering. IOS Press, 2021. http://dx.doi.org/10.3233/atde210182.

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In the blasting demolition processs of high-rise structures, the impact of blasting vibration to the environment and objects to be protected must be effectively controlled, so the blasting vibration signal is deeply analyzed [1]. In this paper, the blasting vibration signal of a chimney is analyzedbased on HHT. The blasting vibration signal is denoised by Empirical Mode Decomposition (EMD)-wavelet threshold, then using Hilbert-Huang Transform (HHT) [2] the measured blasting vibration waveform Hilbert spectrum, marginal spectrum and instantaneous energy graph are draw to analyze the chimney blasting vibration. The results show that the denoising effect of EMD-wavelet threshold is good for blasting vibration signal [3]. HHT method has a good feature identification ability when processing vibration signals, and can reflect the characteristics of data more comprehensively and accurately, which provides convenience for the study of vibration signal data.
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Dik, Olga E., and Alexander D. Nozdrachev. "Chapter 1. Research methods." In Mechanisms of changes in dynamical complexity of physiological signal patterns, 10–35. St. Petersburg State University, 2019. http://dx.doi.org/10.21638/11701/9785288059322.02.

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The first chapter presents methods for analyzing nonstationary physiological signals. Among them are 1) the method of continuous wavelet analysis, which allows obtaining the local and integral distribution of the energy of the wavelet spectrum of the signal over frequencies in a certain time interval, as well as providing information on the cross-wavelet spectrum and wavelet coherence of two signals; 2) methods for assessing the multifractality of a signal by searching for the maxima of the wavelet transform modulus maxima and by analyzing fluctuations relative to the trend; 3) the method of recurrent analysis, which allows to identify the quantitative parameters of the evolution of the signal in time, 4) the method of bifurcation analysis, which allows finding the values of the system parameters at which a qualitative change in the solution of the system occurs, for example, a change in the mode of impulse activity of a neuron.
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Conference papers on the topic "Signal energy spectrum"

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Lu, Yao, Hao He, Jun Wang, and Shaoqian Li. "Energy-efficient dynamic spectrum access using no-regret learning." In Signal Processing (ICICS). IEEE, 2009. http://dx.doi.org/10.1109/icics.2009.5397468.

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Mclean, Christopher, Michael Pauley, and Jonathan H. Manton. "Performance metrics for energy spectrum estimation." In 2017 IEEE Global Conference on Signal and Information Processing (GlobalSIP). IEEE, 2017. http://dx.doi.org/10.1109/globalsip.2017.8308654.

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Yan, Ruqiang, and Robert X. Gao. "A Hybrid Signal Processing Approach to Sensor Data Analysis." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42586.

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This paper presents a hybrid signal processing approach combining the wavelet transform and spectral analysis. A new approach to selecting a mother wavelet for decomposition of vibration signals was demonstrated. Subsequently, the bestsuited decomposition scale was selected based on the energy content of the wavelet coefficients. Subsequently, the envelope spectrum of the wavelet coefficients at the best-suited decomposition scale was used to identify the defect and its location. Experimental analysis of signals from a defect-seeded bearing has shown that the developed approach is more efficient than the conventional spectral analysis techniques.
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Penna, F., C. Pastrone, M. A. Spirito, and R. Garello. "Energy Detection Spectrum Sensing with Discontinuous Primary User Signal." In ICC 2009 - 2009 IEEE International Conference on Communications. IEEE, 2009. http://dx.doi.org/10.1109/icc.2009.5198987.

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Ran, Hu, Liu Zunnian, and Ren Aige. "Experimental study of spectrum analytical method by natural gamma ray energy spectrum." In 2011 4th International Congress on Image and Signal Processing (CISP). IEEE, 2011. http://dx.doi.org/10.1109/cisp.2011.6099983.

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Zhang, Guowei, Ju Liu, Lei Chen, and Weidong Guo. "Efficient energy detector for spectrum sensing in complex Gaussian noise." In Signal Processing (WCSP 2010). IEEE, 2010. http://dx.doi.org/10.1109/wcsp.2010.5633491.

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Grossi, Emanuele, Marco Lops, and Luca Venturino. "Energy efficient communication with radar spectrum sharing." In 2020 IEEE 11th Sensor Array and Multichannel Signal Processing Workshop (SAM). IEEE, 2020. http://dx.doi.org/10.1109/sam48682.2020.9104226.

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Bektas, Cengiz, and Aydin Akan. "Wavelet transform approach to energy based spectrum sensing." In 2012 20th Signal Processing and Communications Applications Conference (SIU). IEEE, 2012. http://dx.doi.org/10.1109/siu.2012.6204424.

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Gamit, Jenishkumar S., and Sameer D. Trapasiya. "Cognitive radio energy based spectrum sensing using MIMO." In 2013 International Conference on Communications and Signal Processing (ICCSP). IEEE, 2013. http://dx.doi.org/10.1109/iccsp.2013.6577147.

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Rugini, Luca, Paolo Banelli, and Geert Leus. "Spectrum sensing using energy detectors with performance computation capabilities." In 2016 24th European Signal Processing Conference (EUSIPCO). IEEE, 2016. http://dx.doi.org/10.1109/eusipco.2016.7760520.

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Reports on the topic "Signal energy spectrum"

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Multiple Engine Faults Detection Using Variational Mode Decomposition and GA-K-means. SAE International, March 2022. http://dx.doi.org/10.4271/2022-01-0616.

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As a critical power source, the diesel engine is widely used in various situations. Diesel engine failure may lead to serious property losses and even accidents. Fault detection can improve the safety of diesel engines and reduce economic loss. Surface vibration signal is often used in non-disassembly fault diagnosis because of its convenient measurement and stability. This paper proposed a novel method for engine fault detection based on vibration signals using variational mode decomposition (VMD), K-means, and genetic algorithm. The mode number of VMD dramatically affects the accuracy of extracting signal components. Therefore, a method based on spectral energy distribution is proposed to determine the parameter, and the quadratic penalty term is optimized according to SNR. The results show that the optimized VMD can adaptively extract the vibration signal components of the diesel engine. In the actual fault diagnosis case, it is difficult to obtain the data with labels. The clustering algorithm can complete the classification without labeled data, but it is limited by the low accuracy. In this paper, the optimized VMD is used to decompose and standardize the vibration signal. Then the correlation-based feature selection method is implemented to obtain the feature results after dimensionality reduction. Finally, the results are input into the classifier combined by K-means and genetic algorithm (GA). By introducing and optimizing the genetic algorithm, the number of classes can be selected automatically, and the accuracy is significantly improved. This method can carry out adaptive multiple fault detection of a diesel engine without labeled data. Compared with many supervised learning algorithms, the proposed method also has high accuracy.
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