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Wyniki wyszukiwania dla: interference
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Analysis of aircraft magnetic interference
PublikacjaThe magnetometric method is used among other things on mobile platforms (planes, helicopters) in military systems and in geological research. Optically-pumped and SQUID magnetometers are used in magnetic systems on airplanes. To be able to attain the sensitivity of modern magnetometers in flight, it is important that maneuver-related magnetic interference effects be minimized. The mathematical model of an aircraft as a source of...
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Analysis of aircraft magnetic interference
PublikacjaThe magnetometric method is used among other things on mobile platforms (planes, helicopters) in military systems and in geological research. Optically-pumped and SQUID magnetometers are used in magnetic systems on airplanes. To be able to attain the sensitivity of modern magnetometers in flight, it is important that maneuver-related magnetic interference effects be minimized. The mathematical model of an aircraft as a source of...
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Broadband interference in speech reinforcement systems
PublikacjaArtykuł podejmuje niedoceniany problem wpływu liczby i rozkładu głośników w systemach nagłośnienia, na jakość przekazu głosowego, czyli na zrozumiałość mowy w audytoriach. Superpozycji przesuniętych w czasie szerokopasmowych sygnałów o tym samym kształcie i lekko różnych wielkościach, które docierają do słuchacza z licznych spójnych źródeł, towarzyszy zjawisko interferencji prowadzące do głębokiej modyfikacji odbieranych sygnałów...
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Multichannel self-optimizing narrowband interference canceller
PublikacjaThe problem of cancellation of a nonstationary sinusoidal interference, acting at the output of an unknown multivariable linear stable plant, is considered. No reference signal is assumed to be available. The proposed feedback controller is a nontrivial extension of the SONIC (self-optimizing narrowband interference canceller) algorithm, developed earlier for single-input, single-output plants. The algorithm consists of two loops:...
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Multifrequency self-optimizing narrowband interference canceller
PublikacjaThe problem of cancellation of a nonstationary sinusoidal interference, acting at the output of a linear stable plant, is considered. It is assumed that disturbance is a multifrequency narrowband signal, and that system output is contaminated with wideband noise. It is not assumed that the reference signal is available. Two disturbance cancelling schemes are proposed, one for disturbances with unrelated frequency components, and...
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Improving the quality of speech in the conditions of noise and interference
PublikacjaThe aim of the work is to present a method of intelligent modification of the speech signal with speech features expressed in noise, based on the Lombard effect. The recordings utilized sets of words and sentences as well as disturbing signals, i.e., pink noise and the so-called babble speech. Noise signal, calibrated to various levels at the speaker's ears, was played over two loudspeakers located 2 m away from the speaker. In...
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Simulation of compensator of magnetic interference caused by an aircraft .
PublikacjaW badaniach geologicznych Ziemi wykorzystuje się m.in. metodę magnetometryczną. Metoda ta polega na pomiarze indukcji magnetycznej na badanym obszarze. Na podstawie rozkładu pola magnetycznego można zlokalizować różnego rodzaje złoża mineralne. Poszukiwania geologiczne wykonywane są na dużych obszarach z wykorzystaniem samolotu. Samolot w swoim otoczeniu zniekształca pole magnetyczne, dlatego też system pomiarowy musi zawierać...
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Ultrawideband transmission in physical channels: a broadband interference view
PublikacjaThe superposition of multipath components (MPC) of an emitted wave, formed by reflections from limiting surfaces and obstacles in the propagation area, strongly affects communication signals. In the case of modern wideband systems, the effect should be seen as a broadband counterpart of classical interference which is the cause of fading in narrowband systems. This paper shows that in wideband communications, the time- and frequency-domain...
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The interference between electrode and poly(ethylene oxide) electrolytes
PublikacjaSpektroskopia impedancyjna zastosowana została do scharakteryzowania granicy faz elektroda-elektrolit poli(oksyetylenowy) zawierający sole litu. Udział rozpuszczalnika w pojemności wewnętrznej warstwy, Cs(σ), dla CH3(OCH2CH2 )nOCH3 DLA N=4,8,10 oraz dla PMEO [(CH2CH2O)mCH2O]m m=5-10 został wyznaczony z wartości pojemności warstwy sztywnej pomniejszonej o udział metalu CM. Wyznaczono wartość pojemności dipolowej Ci(dip) dla PEO...
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Improving AFM images with harmonic interference by spectral analysis
PublikacjaPrzedstawiono sposób usunięcia zakłóceń pojawiających się na obrazach uzyskiwanych z mikroskopu sił atomowych (AFM). Przybliżono kilka metod stosowanych do redukcji zakłóceń w obrazach. Następnie opisano zidentyfikowane zakłócenia harmoniczne oraz zaproponowany sposób ich znaczącej redukcji. W pracy zamieszczono szereg obrazów uzyskanych z mikroskopu AFM ilustrujących efekty powodowane zakłóceniami oraz skuteczność zaproponowanej...
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Narrowband interference suppression in IEEE 802.15.4a ultrawideband receiver
PublikacjaW referacie przedstawiono metodę redukcji wpływu silnych sygnałów wąskopasmowych na jakość transmisji ultraszerokopasmowej w standardzie IEEE 802.15.4a poprzez modyfikację sekwencji impulsów w odbiorniku korelacyjnym. Opisano strukturę rozpatrywanego odbiornika i sposób tworzenia zmodyfikowanych sekwencji wzorcowych, a także przedstawiono wyniki symulacji komputerowych jakości pracy łącza UWB w obecności zakłóceń o charakterze...
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Interference aware bluetooth scatternet (re)configuration algorithm IBLUERA
PublikacjaThis paper presents a new algorithm IBLUEREA, which enables reconfiguration of Bluetooth scatternet to reduce interference. IBLUEREA makes use of the complex model comparing ISM environment efficiency. The mechanism envisages the use of the assessment of the probability of successful (unsuccessful) frame transmission in order to take a decision concerning co-existence of technologies which make use of the same ISM band (here Bluetooth...
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Interference aware Bluetooth scatternet (Re)configuration algorithm IBLUEREA
PublikacjaThe paper presents a new algorithm IBLUEREA, which enables reconfiguration of Bluetooth (BT) scatternet to reduce mutual interferences between BT and Wi-Fi (IEEE 802.11b) networks operating on the same area. IBLUEREA makes use of proposed procedure for modelling ISM environment around a given BT scatternet. The mechanism is based on estimation of the probabilities of successful (unsuccessful) frame transmissions. This determination...
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A comparison of Bluetooth scatternet formation algorithms with reference to interference issues
PublikacjaZe względu na fakt, iż scatternety Bluetooth mogą być tworzone w różnoraki sposób, w artykule podjęto próbę ich porównania pod kątem kilku istotnych parametrów (ze szczególnym uwzględnieniem aspektu potencjalnych interferencji).
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SiMiSnoRNA: Collection of siRNA, miRNA, and snoRNA database for RNA Interference
PublikacjaObjective:The discovery of sequence specific gene silencing which occurs due to the presence of double-stranded RNAs has considerable impact on biology, revealing an unknown level of regulation of gene expression. This process is known as RNA interference (RNAi) or RNA silencing in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecule. Two types of small RNA molecules - small...
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Hybrid SONIC: joint feedforward–feedback narrowband interference canceler
PublikacjaSONIC (self-optimizing narrowband interference canceler) is an acronym of a recently proposed active noise control algorithm with interesting adaptivity and robustness properties. SONIC is a purely feedback controller, capable of rejecting nonstationary sinusoidal disturbances (with time-varying amplitude and/or frequency) in the presence of plant (secondary path) uncertainty. We show that although SONIC can work reliably without...
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Filtering of interference signals of grounding resistance measurement with subharmonic method
PublikacjaOmówiono metodę filtracji zakłóceń o częstotliwości sieciowej wraz z wyższymi harmonicznymi poprzez zastosowanie metody szczególnego próbkowania z podharmonicznym sygnałem pomiarowym.
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Novel approach to interference analysis of glucose sensing materials coated with Nafion
PublikacjaA gold-based sensing platform, TiND | AuNP | Nafion, was prepared as an exemplary electrode material exhibiting a response to glucose in a neutral solution. The change of electrochemical properties after exposure to glucose and interference compounds such as vitamin C, glycine, urea, paracetamol and acetylsalicylic acid was tested.
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Self-optimizing narrowband interference canceller - can reference signal help?
PublikacjaSONIC (Self-Optimizing Narrowband Interference Canceller) is an acronym of the recently proposed active noise control algorithm with interesting adaptivity and robustness properties. SONIC is a purely feedback controller, capable of rejecting nonstationary sinusoidal disturbances (with time-varying amplitudes and/or frequencies) in the presence of plant (secondary path) uncertainties. We show that even though SONIC can work reliably...
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A time-frequency method for detection of electromagnetic field interference on metal constructions.
PublikacjaPrzedstawiono metodę detekcji oddziaływania pola elektromagnetycznego na metalowe konstrukcje podziemne. Polega ona na czasowo-częstotliwościowej analizie rejestrów zmian potencjału źródła pola (np. prądów błądzących) oraz potencjału konstrukcji podziemnej, z wykorzystaniem krótkoczasowej transformaty Fouriera STFT. Wnioski o oddziaływaniu pola na konstrukcję metalową wyciąga się na podstawie analizy uzyskanych widm.
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Detection of stray current field interference on metal constructions using STFT
PublikacjaZaprezentowano metodę detekcji pola prądów błądzących wykorzystującą krótkoczasową transformatę Fouriera STFT. Ten sposób analizy umożliwia wyznaczenie zmian spektralnej gęstości mocy sygnału (np. potencjału konstrukcji) w funkcji czasu. Przedstawiono rezultaty analizy zmian potencjału w polu prądów błądzących generowanych przez trakcję tramwajową. Spektrogramy są kompozycją prążków w łącznej dziedzinie czasu i częstotliwości....
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Electromagnetic interference frequencies prediction model of flyback converter for snubber design
PublikacjaSnubber design for flyback converters usually requires experimental prototype measurements or simulation based on accurate and complex models. In this study simplified circuit modelling of a flyback converter has been described to dimension snubbers in early stage of design process. Simulation based prediction of the transistor and diode ringing frequencies has been validated by measurements in a prototype setup. In that way obtained...
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Factors determining the production testing of high reliability interference supressor capacitors.
PublikacjaPrzyjęto nieliniowości i właściwości szumowe kondensatora jako kryteria selekcji kondensatorów przeciwzakłóceniowych na klasy o zróżnicowanej niezawodności. Poprawia to proces oceny jakości kondensatorów o podwyższonej niezawodności. Przedstawiono zastosowanie technik pomiaru nieliniowości i szumów w systemie do produkcyjnego testowania kondensatorów przeciwzakłóceniowych o podwyższonej niezawodności. Przytoczono wybrane wyniki...
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Narrowband Transmission Quality in Presence of Modified IEEE 802.15.4a Impulse Radio Interference
PublikacjaThis paper presents results of measurement of narrowband transmission quality in presence of impulse radio UWB interference. IEEE 802.15.4a UWB signal is being used as interferer, also with frame structure modifications which lead to change spectrum of the interference. Equations and coefficients which allow to calculate ratio between power of useful and interference signal are also presented.
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Merging extremum seeking and self-optimizing narrowband interference canceller - overdetermined case
PublikacjaActive cancellation systems rely on destructive interference to achieve rejection of unwanted disturbances entering the system of interest. Typical practical applications of this method employ a simple single input, single output arrangement. However, when a spatial wavefield (e.g. acoustic noise or vibration) needs to be controlled, multichannel active cancellation systems arise naturally. Among these, the so-called overdetermined...
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Application of TMS320c67xx signal processors for SONIC-self-optimizing narrowband interference canceler
PublikacjaThe paper presents a laboratory system for testing active control algorithms of acoustics noise in ducts. An applied algorithm - self-optimizing narrowband interference canceller (SONIC), allows one to remove narrowband disturbances of constant or slowly time-varying frequencies. Example experimental results of using the laboratory system for supression of sinusoidal disturbance are described. An electronic part of the system was...
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Propagation Loss and Interference Analysis for 5G Systems in the Context of C-ITS System Implementation
PublikacjaThe article presents the concept of implementing subsequent phases of services for the C-ITS system (the Cooperative Intelligent Transport Systems), based on the European Parliament resolution of March 2018. Next, the 5G systems, in the context of their possible cooperation with C-ITS systems, were discussed. Numerical propagation analysis was performed for V2V and V2I type communication based on two different propagation models....
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FPGA-Based System for Electromagnetic Interference Evaluation in Random Modulated DC/DC Converters
PublikacjaField-Programmable Gate Array (FPGA) provides the possibility to design new “electromagnetic compatibility (EMC) friendly” control techniques for power electronic converters. Such control techniques use pseudo-random modulators (RanM) to control the converter switches. However, some issues connected with the FPGA-based design of RanM, such as matching the range of fixed-point numbers, might be challenging. The modern programming...
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Nanoindentation tests titanium alloy Ti-6Al-4V after interference laser treatment
PublikacjaThe study aimed was to assess selected mechanical properties of surface layers obtained after interference laser treatment – DLIL of titanium alloy Ti-6Al-4V used for implants. The samples were melted in still air at room temperature, for this purpose Nd:YAG laser was used, the number of laser shots was variable. Next, nanoindentation tests were performed, based on which Young’s modulus and nanohardness in the obtained surface...
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SONIC - Self-optimizing narrowband interference canceler: comparison of two frequency tracking strategies
PublikacjaThis paper presents a new approach to rejection of complex-valued sinusoidal disturbances acting at the output of a discrete-time linear stable plant with unknown and possibly time-varying dynamics. It is assumed that both the instantaneous frequency of the sinusoidal disturbance and its amplitude may be slowly varying with time and that the output signal is contaminated with wideband measurement noise. The proposed disturbance...
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Techniques of interference reduction in probe system for wafer level noise measurements of submicron semiconductor devices.
PublikacjaPrzedstawiono skrótowo system do ostrzowych pomiarów szumów struktur submikronowych. Znaczny wpływ na pomiary ostrzowe mają zakłócenia i szumy własne systemu, zwłaszcza zakłócenia o wysokim poziomie wpraowadzane przez ostrza (fluktuacje rezystancji styków ostrza do struktury powodowane przez wibracje i udary mechaniczne w środowisku pomiarowym)i środowisko elektromagnetyczne. Zakłócenia okresowe powodowane przez wibracje i pola...
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Protective and Suppressing Electromagnetic Interference Properties of Epoxy Coatings Containing Nano-Sized NiZn Ferrites
PublikacjaNano-crystalline ferrites with the chemical formula NixZn(1−x)Fe2O4, where x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, were synthesized using a co-precipitation method. The obtained ferrites were investigated by X-ray diffraction (XRD). The corrosion inhibiting behavior of nano-sized ferrites was tested using carbon steel samples and 10% aqueous ferrite extracts. Results were compared with previous data obtained for micro-sized ceramic ferrites....
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FFT analysis of temperature modulated semiconductor gas sensor response for the prediction of ammonia concentration under humidity interference
PublikacjaThe increasing environmental contamination forces the need to design reliable devices for detecting of the volatile compounds present in the air. For this purpose semiconductor gas sensors, which have been widely used for years, are often utilized. Although they have many advantages such as low price and quite long life time, they still lack of long term stability and selectivity. Namely, environmental conditions have significant...
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Eco-Friendly Electromagnetic Interference Shielding Materials from Flexible Reduced Graphene Oxide Filled Polycaprolactone/Polyaniline Nanocomposites
PublikacjaHybrid nanocomposites have the unique ability of enhancing material properties due to the existing synergistic effect of the fillers. In this study, the authors report such an eco-friendly hybrid nanocomposite comprising of polyaniline and reduced graphene oxide in polycaprolactone. The conducting polyaniline improved the processability of polycaprolactone, and the final composites were prepared by incorporating graphene oxide...
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THE INFLUENCE OF HOUSING ARRANGEMENT AND INTERFERENCE ON PRELOAD AND THEORETICAL LIFETIME OF A SYSTEM OF TAPER ROLLER BEARINGS OF A HIGH SPEED SHAFT OF A WIND TURBINE GEARBOX
PublikacjaA system of two taper roller bearings can carry loads with a high ratio of axial load to radial load. Such a system was proposed for a wind turbine gearbox following the poor durability of original bearing design with the aim of increasing durability. Because of size limits, a proposed system is composed of two different taper roller bearings. Standard manufacturers’ catalogues do not provide information on recommended preload...
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Interference-Free Determination of Trace Copper in Freshly Ripened Honeys by Flame Atomic Absorption Spectrometry Following a Preconcentration by Solid-Phase Extraction and a Two-Step Elution Process
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A new time-frequency detection method of stray current field interferenceon metal structures.
PublikacjaA new detection method has been presented of stray current field interference on underground metal structures. The method employs short time Fourier transformation (STFT). This method of analysis allows determination of signal spectral power density changes (e.g., structure potential) in the function of time. In the paper results have been presented of total time–frequency analysis of a pipeline potential in a stray current field...
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Mixed electromagnetic - circuits modeling and parallelization for rigorouscharacterization of cosite interference in wireless communication channels. W: UGC 2002 Homepage [online]. Department of Defense High Performance Com- puting Modernization Program. Users Group Conference 2002. Austin, Texas, USA. June 10-14, 2002. [Dostęp: 15 grudnia**2002]. Dostępny w World Wide Web: http://www.hpcmo.hpc.mil/Htdocs/UGC/UGC02/paper/[45 slajdów]. Modelowanie układów elektromagnetycznych i zrównoleglanie w celu określenia wzajemnych oddziaływań w bezprzewodowych kanałach komunikacyjnych.
PublikacjaRównoległe działanie sąsiadujące modułów nadawczo-odbiorczych typowo prowa-dzi do efektów ubocznych z powodu wzajemnych oddziaływań, które obniżają pa-rametry sieci. W celu scharakteryzowania takich efektów, zaprezentowano roz-wiązanie równań Maxwella w dziedzinie czasu z modelowaniem efektów nielinio-wych.
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Reduction of spectral interferences in atmospheric pressure glow discharge optical emission spectrometry
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Aggregated conducted interferences generated by group of asynchronous drives with deterministic and random modulation
PublikacjaThis paper addresses problems linked with electromagnetic interferences generated by group of three adjustable speed drives fed by frequency converters with deterministic and random modulation. Based on the experimental results it has been shown that decreasing of the conducted interferences in a case of random modulation is measuring phenomenon linked with selectivity of the EMI receiver.
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Optimisation of pressurised liquid extraction for elimination of sulphur interferences during determination of organotin compounds in sulphur-rich sediments by gas chromatography with flame photometric detection
PublikacjaOpracowano metodę analizy osadów dennych na zawartość związków cynoorganicznych (MBT, DBT, TBT, MPhT, DPhT, TPhT) przy użyciu przyspieszonej ekstrakcji rozpuszczalnikiem i chromatografii gazowej z detektorem płomieniowo-fotometrycznym. Detektor ten pozwala selektywnie wykrywać niewielkie ilości pochodnych cynoorganicznych. Niestety, bardzo często spotykana w osadach siarka oraz jej pochodne zakłócają sygnał detektora. Z tego względu...
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The conducted EMI in DC-DC converters
PublikacjaThis book presents the phenomena of conducted electromagnetic interference (EMI) generation in DC-DC converters. The measurement and simulation are used to analyze the impact of the most important parameters on the character, level and propagation path of interference. In this book, the analysis of the interference generation and propagation is presented on the example of three basic converters. The wide banded behavior of all...
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Swapping Space for Time: An Alternative to Time-Domain Interferometry
PublikacjaYoung's double-slit experiment [1] requires two waves produced simultaneously at two different points in space. In quantum mechanics the waves correspond to a single quantum object, even as complex as a big molecule. An interference is present as long as one cannot tell for sure which slit is chosen by the object. The more we know about the path, the worse the interference. In the paper we show that quantum mechanics allows for...
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Narrowband Transmission Quality in Presence of Modified IEEE 802.15.4a UWB Signal
PublikacjaThis paper presents results of measurement of narrowband transmission quality in presence of impulse radio UWB interference. In the first part of paper, unmodified IEEE 802.15.4a IR UWB signal is used. Then some modification of transmitted pulse sequence is proposed, which allow to reduce UWB power spectral density at frequency of narrowbandtransmission. Finally narrowband transmission quality in presence of modified ultrawideband...
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Reception of GNSS Signals Under Jamming Conditions
PublikacjaThe article focuses on performance of Global Navigation Satellite System receivers in environment where intentional interference is present. First part is a general description of GNSS systems. Secondly, types of positioning service disturbances are specified. In the third part authors present a scheme of measurement stand which is used to evaluate the influence of interference on reception of navigation signals. Next, research...
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Narrowband Transmission Quality in Presence of Modified IEEE 802.15.4a UWB Signal
PublikacjaThis paper presents results of measurement of narrowband transmission quality in presence of impulse radio UWB interference. In the first part of paper, unmodified IEEE 802.15.4a IR UWB signal is used. Then some modification of transmitted pulse sequence is proposed, which allow to reduce UWB power spectral density at frequency of narrowband transmission. Finally narrowband transmission quality in presence of modified ultrawideband...
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Multichannel self-optimizing active noise control scheme
PublikacjaThe problem of cancellation of a nonstationary sinusoidal interference, acting at the output of an unknown multivariable linear stable plant, is considered. The proposed cancellation scheme is a nontrivial extension of the SONIC (self-optimizing narrowband interference canceller) algorithm, developed earlier for single-input, single-output plants. In the important benchmark case - for disturbances with randomwalk-type amplitude...
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Ochrona odbiorników GNSS przed zakłóceniami celowymi
PublikacjaArtykuł dotyczy zastosowania algorytmów przestrzennego cyfrowego przetwarzania sygnałów dla potrzeb selektywnej eliminacji sygnałów zakłócających pracę odbiorników nawigacji satelitarnej GNSS. Omówiono podatność tych odbiorników na ataki elektroniczne typu zagłuszanie oraz spoofing. Polegają one na celowej emisji sygnałów niepożądanych w paśmie pracy systemu. Następnie przedstawiono koncepcję przeciwdziałania tego rodzaju zakłóceniom...
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Method of sacrificial anode dual transistor-driving in stray current field
PublikacjaIn order to control a magnesium anode in a stray current interference field, a dual transistor driving system has been proposed. It consisted of a combination of PNP and NPN transistors. Dual transistor driven system and direct anode to cathode connection were electrochemically tested in 3% NaCl solution. The dual transistor driven system increased the anode efficiency and reduced hydrogen evolution and the risk of embrittlement....
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Improved jamming resistance using electronically steerable parasitic antenna radiator
PublikacjaThis paper presents an idea of using an Electronically Steerable Parasitic Antenna Radiator (ESPAR) for jamming suppression in IEEE 802.11b networks. Jamming (intentional interference) attacks are known to be effective and easy to perform, which may impose connectivity problems in applications concerning Internet of Things (IoT). In our paper, theoretical considerations are presented and the results of experiments performed in...