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Search results for: ASYNCHRONOUS SIGNALS
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Silence/noise detection for speech and music signals
PublicationThis paper introduces a novel off-line algorithm for silence/noise detection in noisy signals. The main concept of the proposed algorithm is to provide noise patterns for further signals processing i.e. noise reduction for speech enhancement. The algorithm is based on frequency domain characteristics of signals. The examples of different types of noisy signals are presented.
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A method of identification of RTS components in noise signals
PublicationW artykule przedstawiono oryginalną metodę wydzielania szumu RTS (Random Telegraph Signal) - dwupoziomowego lub wielopoziomowego - z sygnału szumowego. Podstawą oceny jakości metody jest założenie, że wartości chwilowe szumu RTS mają rozkład niegaussowski natomiast pozostała część sygnału ma rozkład gaussowski.Algorytm identyfikacji wielopoziomowych szumów RTS w sygnałach szumowych małej częstotliwości oparty został na aproksymacji...
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Selection of excitation signals for high-impedance spectroscopy
PublicationA method of fast impedance spectroscopy of technical objects with high impedance (|Zx| > 1 GOhm) is evaluated in this paper. An object is excited with a signal generated by a digital-to-analog converter (DAC) located on the U2531A DAQ module. Response signals proportional to current flowing through and voltage across the measured object are sampled by analog-to-digital converters (ADC) in the DAQ module. The object impedance spectrum...
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Laboratory Stand for Wideband Analysis Radiocommunication Signals
PublicationA laboratory stand for wideband analysis radiocommunication signals is presented in the paper. The stand is designed for signals acquisition in wide spectrum and research a field of digital signal processing. Procedures used for simultaneous acquiring many frequency channels in selected wide band are described. The method of detection of direct sequence spread spectrum signals (DS SS) which power spectral density is lower than...
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Usage of concentrated spectrogram for analysis of acoustical signals
PublicationA novel precise method of signal analysis in the time-frequency domain is presented. A signal energy distribution is estimated by discard and displacement of energy parts of the classical spectrogram. A channelized instantaneous frequency and a local group delay are used in order to energy replacement. Additionally, newly introduced representations such as: a channelized instantaneous bandwidth and a local group duration are used...
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Detection Range of Intercept Sonar for CWFM Signals
PublicationStealth in military sonars applications may be ensured through the use of low power signals making them difficult to intercept by the enemy. In recent years, silent sonar design has been investigated by the Department of Marine Electronic Systems of the Gdansk University of Technology. This article provides an analysis of how an intercept sonar operated by the enemy can detect silent sonar signals. To that end a theoretical intercept...
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Identification of models and signals robust to occasional outliers
PublicationIn this paper estimation algorithms derived in the sense of the least sum of absolute errors are considered for the purpose of identification of models and signals. In particular, off-line and approximate on-line estimation schemes discussed in the work are aimed at both assessing the coefficients of discrete-time stationary models and tracking the evolution of time-variant characteristics of monitored signals. What is interesting,...
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Laboratory stand for wideband analysis radiocommunication signals
PublicationA laboratory stand for wideband analysis radiocommunication signals is presented in the paper. The stand is designed for signals acquisition in wide spectrum and research a field of digital signal processing. Procedures used for simultaneous acquiring many frequency channels in selected wide band are described. The method of detection of direct sequence spread spectrum signals (DS SS) which power spectral density is lower than...
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Annual signals observed in regional GPS networks
PublicationAbstract: This paper describes analyses concerning annual signals in GPS-derived coordinates. The data was processed in the Military University of Technology Local Analysis Centre with Bernese 5.0 software. We used observations from 129 permanent GPS stations which belong to the Polish Active Geodetic Network (ASG-EUPOS), for the period of GPS weeks 1465-1729, corresponding to about 5 years. The annual signals have been estimated...
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Detection of impulsive disturbances in archive audio signals
PublicationIn this paper the problem of detection of impulsive disturbances in archive audio signals is considered. It is shown that semi-causal/noncausal solutions based on joint evaluation of signal prediction errors and leave-one-out signal interpolation errors, allow one to noticeably improve detection results compared to the prediction-only based solutions. The proposed approaches are evaluated on a set of clean audio signals contaminated...
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Application of nonlinearity measures to chemical sensor signals
PublicationSzumy rezystancji sensorów gazu zawierają istotną informację, która może być przedstawiona nie tylko przez ich gęstość widmową mocy. Analiza tych szumów za pomocą różnych miar nieliniowości może prowadzić do znacznego wzrostu selektywności i czułości czujników gazu. Stwierdzono, że dla dostępnych na rynku czujników gazu zastosowanie funkcji bispektrum dostarcza dodatkowej informacji, potrzebnej do detekcji różnych gazów. Analizując...
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Identification of models and signals robust to occasional outliers
PublicationIn this paper estimation algorithms derived in the sense of the least sum of absolute errors are considered for the purpose of identification of models and signals. In particular, off-line and approximate on-line estimation schemes discussed in the work are aimed at both assessing the coefficients of discrete-time stationary models and tracking the evolution of time-variant characteristics of monitored signals. What is interesting,...
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Adaptive filter for reconstruction of stereo audio signals.
PublicationArtykuł poświęcony jest omówieniu metody rekonstrukcji zakłóconych impulsowo sygnałów stereofonicznych. W pracy zdefiniowano model sygnału stereofonicznego i przedstawiono zaprojektowany dla tego modelu filtr Kalmana. Przedstawiono modyfikacje filtru, w wyniku których algorytm dokonuje rekonstrukcji zakłóconego impulsowo sygnału w jednym kanale z wykorzystaniem dodatkowej informacji zawartej w niezakłóconych próbkach sygnału pochodzącego...
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Transmission of digital signals in a nonstationary hydroacoustic channel.
PublicationZ telekomunikacyjnego punktu widzenia właściwości transmisyjne kanału hydroakustyczny są ograniczone przez występowanie wielokrotnych odbić fali dźwiękowej od dna i powierzchni wody oraz niestacjonarność wprowadzaną głównie przez ruch powierzchni wody. Artykuł przedstawia model własności transmisyjnych kanału. Wprowadzono niestacjonarność do odpowiedzi impulsowych kanału przez założenie przypadkowej zmienności czasów przyjścia...
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Polyarmonic model of synchronous generator for analysis of autonomous power generation systems
PublicationAbstract: This paper presents the polyharmonic modelling of synchronous generator (SG) in machine variables. The simple geometry and windings physical layout has been used for inductance calculations of a salient-pole SG. The main advantage of this model is the ease of describing an autonomous power generation system (APGS) in terms of its topology and thus providing effective analysis at the static and dynamic states, both for...
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Nonlinear Model of Synchronous Generator for Autonomous Electrical Power Systems Analysis
PublicationThis paper presents the nonlinear lookup table model for synchronous generator (SG) analysis. The saturation effects of the SG magnetic circuit have been considered. The saturated characteristic of the SG magnetic circuit are based on the open circuit saturation curve for magnetizing inductances. The model has been implemented into the Synopsys/Saber software using the MAST modelling language. To implement the no-load voltage characteristic...
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Identification and non-integer order modelling of synchronous machines operating as generator
PublicationThis paper presents an original mathematical model of a synchronous generator using derivatives of fractional order. In contrast to classical models composed of a large number of R-L ladders, it comprises half-order impedances, which enable the accurate description of the electromagnetic induction phenomena in a wide frequency range, while minimizing the order and number of model parameters. The proposed model takes into account...
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Possibilities of using SVC compensators for synchronous generators rotors oscillations damping.
PublicationThe article presents the idea of using static var compensators (SVC) for damping generators rotors oscillations. A novel SVC controller structure is proposed to provide better dynamic performance of the power system. A tests results are shown for proposed controller structure, that was carried out in a three-machine power system model as well as in multi-machine model of Polish Power System.
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Design of synchronous generator voltage regulator based on H control theory
PublicationSystemy dużej mocy są z reguły systemami o dużej nieliniowości. Wynika to z dynamiki takiego obiektu jak również jego konfiguracji itd. Istnieje wiele metod umożliwiających sterowanie czy testowanie zaprojektowanych generatorów. W artykule analizowana jest metoda projektowania regulatora napięcia w oparciu o H. Wyniki symulacji są zadowalające, ponieważ tak zaprojektowany regulator lepiej tłumi kołysania elektromechaniczne niż...
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Estimation of Synchronous Generator and AVR Parameters Based on Gradient and Genetic Methods
PublicationThe author present a method for the estimation of selected synchronous generator model and AVR parameters using a gradient and a genetic algorithm. The paper shows an example of model parameter estimation for a turbogenerator, based on the generator voltage time responses obtained during an active and reactive power rejection test
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Models of Brushless Synchronous Generator for Studying Autonomous Electrical Power System
PublicationThis is a PhD dissertation. The work presented in this monograph was carried out at the Department of Power Electronics and Electrical Machines, Faculty of Electrical and Control Engineering at the Gdansk University of Technology. Developed during the research models of brushless synchronous generator ware verified using FEM based simulations and measurements conducted on the prototype generator. The main focus of the research...
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Comparative Study of Integer and Non-Integer Order Models of Synchronous Generator
PublicationThis article presents a comparison between integer and non-integer order modelling of a synchronous generator, in the frequency domain as well as in the time domain. The classical integer order model was compared to one containing half -order systems. The half-order systems are represented in a Park d-q axis equivalent circuit as impedances modelled by half-order transmittances. Using a direct method based on the approximation...
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Research on a permanent magnet assisted synchronous reluctance machine with hybrid excitation
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Rotor-Flux Vector based Observer of Interior Permanent Synchronous Machine
PublicationThe sensorless control system of the interior permanent magnet machine is considered in this paper. The control system is based on classical linear controllers. In the machine, there occurs non-sinusoidal distribution of rotor flux together with the slot harmonics, which are treated as the control system disturbances. In this case, the classical observer structure in the (d-q) is unstable for the low range of rotor speed resulting...
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Simulation of influence of the air gap asymmetryon voltage waveforms of a synchronous machine
PublicationResults of simulation of a synchronous generator with the air gap asymmetry characterised by eccentricity are presented in the paper. The Lagrange's energy method has been used in derivation of the model equations. Analysis of influence of the air gap asymmetry on characteristics of self and mutual inductances of windings, as well as analysis of induced voltage waveforms as a function of the air gap asymmetry have been performed....
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Design of synchronous generator voltage regulator based on h control theory
PublicationThe power system is highly nonlinear system, which dynamics depends on system network configuration, system loading…etc. To overcome the above mentioned difficulties and to fulfill the performance requirements the different control methods are considered and tested for application to generating control unit. Application of the H optimization method to automatic voltage regulator is studied in this paper. Simulation results have...
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DIGITAL SIGNAL PROCESSING
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Long-range dependencies in heart rate signals—revisited
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Using concentrated spectrogram for analysis of audio acoustic signals
PublicationThe paper presents results of time-frequency analysis of audio acoustic signals using the method of Concentrated Spectrograph also known as ''Cross-spectral method'' or ''Reassignment method''. Presented algorithm involves signal's local group delay and channelized instantaneous frequency to relevantly redistribute all Short-time Fourier transform lines in time-frequency plain. The main intention of the paper is to compare various...
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TDOA Navigation Using CDMA2000 Signals – Experimental Results
PublicationThis paper presents results of an experiments on the possibility to estimate position of a CDMA2000 receiver on the basis of TDOA measurements. The hardware and software structure of a navigation receiver used during investigation is briefly described with focus on drawbacks and limitations. The main part of this paper contains basic information about CDMA2000 network in northern Poland, which signals were recorded during tests...
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Detection of broadband signals in the field of aperture and array systems.
PublicationAnteny i szyki anten w dolnopasmowych systemach hydroakustycznych wnoszą istotne zniekształcenia liniowe wpływające na możliwości detekcji sygnałów szerokopasmowych. W artykule analizowany jest charakter takich zniekształceń metodą przestrzenno - czasowych odpowiedzi impulsowych. Sygnał odbierany w różnych kierunkach przestrzeni poddano filtracji na dwa sposoby z filtrem dopasowanym do sygnału nadawanego i filtrem dopasowanym...
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Quality prediction of foil capacitors by acoustic emission signals
PublicationJakość i trwałość kondensatorów foliowych jest zależna od ich warunków pracy (np. nadmiarowego napięcia pracy, temperatury, wilgotności) oraz od potencjalnych defektów wprowadzonych na różnych etapach wytwarzania kondensatorów. Nieustanny nacisk na wzrost jakości wytwarzanych elementów przy jednoczesnej redukcji kosztów wytwarzania oznacza, że nowe, tanie i szybkie metody predykcji jakości tych elementów są mocno poszukiwane. W...
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Wavelet filtering of signals without using model functions
PublicationThe effective wavelet filtering of real signals is impossible without determining their shape. The shape of a real signal is related to its wavelet spectrum. For shape analysis, a continuous color wavelet spectrogram of signal level is often used. The disadvantage of continuous wavelet spectrogram is the complexity of analyzing a blurry color image. A real signal with additive noise strongly distorts the spectrogram based on continuous...
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Stress Detection of Children With ASD Using Physiological Signals
PublicationThis paper proposes a physiological signal-based stress detection approach for children with autism spectrum disorder (ASD) to be used in social and assistive robot inter- vention. Electrodermal activity (EDA) and blood volume pulse (BVP) signals are collected with an E4 smart wristband from children with ASD in different countries. The peak count and signal amplitude features are derived from EDA signal and used in order to detect...
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Graph Representation Integrating Signals for Emotion Recognition and Analysis
PublicationData reusability is an important feature of current research, just in every field of science. Modern research in Affective Computing, often rely on datasets containing experiments-originated data such as biosignals, video clips, or images. Moreover, conducting experiments with a vast number of participants to build datasets for Affective Computing research is time-consuming and expensive. Therefore, it is extremely important to...
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Digital measurements of the feedback signals for observing behaviour of a drive.
PublicationW pracy omówiono sposoby badań przebiegu ruchu realizowanego przez napęd, w tym poprzez pomiar sygnałów sprzężeń zwrotnych. Przedstawiono różne typy błędów pomiaru sygnałów sprzężeń zwrotnych i ich oddziaływanie na wyniki.
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New approach to localization of clicks in archive speech signals.
PublicationPrzedstawiono problem lokalizacji zniekształceń impulsowych w archiwalnych sygnałach mowy. Pokazano, że detekcja oparta na dwuzakresowym modelu autoregresyjnym i przetwarzanie dwukierunkowe pozwala uzyskać znaczącą poprawę działania w stosunku do istniejących metod lokalizacji zniekształceń.
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Application of CDMA modulated signals in seafloor remote sensing
PublicationW artykule omowiono zastosowanie modulacji CDMA w procesie detekcji echa od dna. Wyniki badan przedstawone zostaly dla symulacji z wykorzystaniem symulatora BORIS.
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Application of hybrid signals processors to speech and hearing aids
PublicationDzięki postępowi w technice Cyfrowych Procesorów Sygnałowych (ang. DSP) stało się możliwe budowanie miniaturowych protez słuchu i mowy. Mimo niewielkich wymiarów procesory te są w stanie wykonywać złożone algorytmy. Ich dodatkową zaletą jest łatwość zmiany oprogramowania, a co za tym idzie łatwość zmiany dziedziny zastosowań. W pracy skupiono się na zagadnieniach związanych z projektowanie i implementacją algorytmów mających zastosowanie...
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Journal of Medical Signals and Sensors
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MATHEMATICS OF CONTROL SIGNALS AND SYSTEMS
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A model development and experimental verification for a vapour microturbine with a permanent magnet synchronous generator
PublicationVapour microturbines with permanent magnet synchronous generators are implemented in micropower plants for dispersed power generation systems. The dynamic model of such a microturbine set was developed and presented. The developed relations result from the generic equations. Experimental data for two different working medium were used for model verification. A microturbine set model was tested during the changes in the parameters...
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Nonlinear model of a synchronous generator for analysis of more electric aircraft power systems
PublicationA nonlinear model for studying a variable-speed synchronous generator (SG) in more electric aircraft (MEA) power system has been developed. The saturation effects of the SG magnetic circuit have been considered. The model has been implemented in the Synopys/Saber simulation environment. The modelling language MAST has been used to elaborate the SG model. The model exhibit a network with the same number of external terminals/ports...
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Technical evaluation of marine auxiliary diesel engine on the basis of parameters synchronous generator
PublicationThe article presents a method for evaluating the technical condition of selected structural elements of the reciprocating internal combustion engine driving a synchronous generator. Th results of measurements of the electric generator parameters are the diagnostic information source. On this basis it is possible to determine the instantaneous angular speed marine engine crankshaft which, in turn, is the basis for reasoning about...
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Synchronous generator model taking into account the non-uniform saturation of the pole shoes
PublicationFor the evaluation of modern electric power systems with regard to their behavior, weight, and reliability a novel modeling and simulation tools have been developed. The paper presents circuit model of synchronous generator taking into account both the non-sinusoidal distribution of the stator and rotor winding, and non-uniform saturation of the pole shoes. This model is suitable for simulation of both salient and no-salient pole...
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Low speed permanent magnet synchronous generator for vertical axis wind turbine
PublicationThe paper presents design process and tests of a prototype low speed permanent magnet synchronous generator (PMSG) dedicated for the innovative vertical-axis wind turbine. The rated data of the designed generator are following: power - 15 kVA, voltage - 400 V (Y), rotation speed - 93.75 rpm. The design assumptions, chosen results of the design process and experimental tests of the prototype PMSG are presented. The considered PMSG...
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THE METHOD OF MEASURING THE MEMBRANE COVER GEOMETRY USING LASER SCANNING AND SYNCHRONOUS PHOTOGRAMMETRY
PublicationThe authors present the experience and results of field studies carried out at the technical acceptance of Forest Opera (name in Polish: Opera Leśna) in Sopot (Poland). An unusual design of covering made in the form of “Sheerfill I” technical fabric membrane required spanned in the form of sails, required the use of terrestrial laser scanning. Such approach allowed for the fast and accurate record of the surface of individual panels...
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A method for the three-dimensional and synchronous resolution of functional and spatial matters in architectural design
PublicationThe article discusses the issue of applied methods of teaching architectural design at Polish universities. The authors review the common methods based on conceptual drawings solving design problems in only two dimensions. After completing the floor plans' sketching process carried out in 2D way the 3D virtual models are made - seldom cardboard mock-ups - to illustrate the final spatial form of the designed object. At the Faculty...
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Design of synchronous generator two inputs regulator based on hinf control theory.
PublicationThe power system is highly nonlinear system, its dynamics depends on system network configuration, system loading… etc. To overcome the above mentioned difficulties and fulfill the performance requirements the different control methods are considered and tested for design of synchronous generator control system. Application of the H optimization method to synchronous generator regulator based on measurement of generator voltage...
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The computer numerical control system with permanent magnet synchronous motor servo-drives.
PublicationPrzedstawiono układ serwonapędów wieloosiowej maszyny sterowanej numerycznie. W układzie wykorzystano silniki synchroniczne z magnesami trwałymi oraz procesory synałowe DSP. Omówiono algorytmy sterowania nadrzędnego oraz problemy sterownia silnika PMSM.