Search results for: FREQUENCY ANALYSIS
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Application of the Least Squares Method to the approximation of equally spaced samples in frequency measurement approach
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Digital processing of pulse signal from light-to-frequency converter under dynamic condition
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The use of a static electrical energy meter as a transducer of active power to a pulse frequency signal
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Effect of mid-frequency discharge assistance on dual-high power impulse magnetron sputtering
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Feature-Based Characterisation of Turned Surface Topography with Suppression of High-Frequency Measurement Errors
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Proposals of Frequency-Based and Direction Methods to Reduce the Influence of Surface Topography Measurement Errors
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Experimental evaluation of high frequency side scan sonar as object search and identification tool
PublicationPraca prezentuje wyniki badań laboratoryjnych sonaru bocznego jako narzędzia dla pojazdu podwodnego, służącego do poszukiwań i identyfikacji obiektów leżących na dnie, w bliskich odległościach.
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Experimental frequency-domain characterization of fundamental guided mode parameters in coupled coplanar waveguide
PublicationW pracy przedstawiono metodę wyznaczania współczynnika propagacji oraz impedancji charakterystycznej rodzajów podstawowych w strukturze sprzężonych linii koplanarnych. Metoda, oparta o wykorzystanie specjalnych struktur pobudzających oraz klasyczne pomiary w dziedzinie częstotliwości przy pomocy wektorowego analizatora sieci wykazała przydatność do wyznaczania zależnych od częstotliwości parametrów struktury.
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Numerical Estimate of the Spectral Resonance Structure Frequency Scale of Natural ULF Magnetic Field
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Determination of Complex Permeability of Silicon Steel for Use in High-Frequency Modeling of Power Transformers
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The Impact of Organizational Culture on Bicycle Commuting Frequency: The Research Based on Example of Three IT companies
PublicationThis chapter describes a study on work-related factors affecting employees’ decision on bicycle commuting. Employees’ transport choices are related to organizational culture. This chapter refers to E. Schein’s definition of organizational culture model. The study was made in order to determine the impact of specific levels of organizational culture on the transport behavior of employees. It is based on a survey performed in three...
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4x4 Butler matrix in microstrip-slot technology for 5.4 - 5.7 GHz frequency band
PublicationW pracy zaprezentowano projekt, realizację oraz wyniki pomiarów parametrów 8-wrotowej, mikropaskowej matrycy Butlera wykonanej w technice wielowarstwowej. Poprzez odpowiednie rozmieszczenie wrót układu oraz zastosowanie sprzęgaczy wykorzystujących efekt sprzężenia poprzez szczelinę w płaszczyźnie wspólnej masy wyeliminowano konieczność zastosowania skrzyżowań linii mikropaskowych. Zrealizowany układ wydaje się obiecujący, ze względu...
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Fast frequency sweep based on the model order reduction technique for calculating scattering parametersjinjFDFDj
PublicationArtykuł prezentuje ulepszoną, efektywną metodę przemiatania częstotliwościowego dla metody FDFD. Liczba równań opisujących analizowaną strukturę jest redukowana za pomocą metody redukcjirzędu modeli, a następnie macierz wynikowa jest diagonalizowana. Kosztowne czasowo odwracanie dużych macierzy jest zastąpione prostym mnożeniem małej macierz diagonalnej przez wektor. Zaprezentowana metoda przemiatania częstotliwościowego może...
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Charakterystyki pojemnościowo-zasięgowo sieci komórkowej LTE wykorzystującej metodę Partial Frequency Reuse
PublicationW referacie przedstawiono wyniki badań charakterystyk pojemnościow-zasięgowych sieci komórkowej LTE, w której zastosowano metodę ponownego wykorzystania pasma PFR. Wyniki badań umożliwiają ocenę efektywności wykorzystania zasobów fizycznych, w zależności od metody podziału obszaru komórki na podobszary o różnym sposobie przydziału tych zasobów. Mogą być one użyteczne do oceny efektywności metody PFR oraz do projektowania i optymalizacji...
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A Substrate Integrated Waveguide (SIW) Bandpass Filter in A Box Configuration With Frequency-Dependent Coupling
PublicationThis letter presents the design of a microwave bandpass filter with frequency-dependent coupling implemented in substrate integrated waveguide (SIW) technology. The proposed filter implements a four-pole generalized Chebyshev filtering function with two transmission zeros. Resonators are arranged in an extended box configuration with dispersive coupling on a main signal path, which produces an extra zero in comparison to classical...
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Design of high frequency OTA in 130nm CMOS technology with single 1.2v power supply
PublicationW artykule przedstawiono wzmacniacz transkonduktancyjny OTA zasilany niskim napięciem i przeznaczony do użycia w filtrach czasu ciągłego w zakresie wysokich częstotliwości przetwarzanych sygnałów. Stopień wejściowy zbudowany jest w oparciu o inwertery CMOS. Wartość transkonduktancji wzmacniacza jest przestrajana z wykorzystaniem efektu podłożowego tranzystorów. Omówiono również układ dostrajania wzmacniacza. Brak wewnętrznych węzłów...
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SONIC - Self-optimizing narrowband interference canceler: comparison of two frequency tracking strategies
PublicationThis 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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Nonlinear generation of non-acoustic modes by low-frequency sound in a vibrationally relaxing gas
PublicationTwo dynamic equations referring to a weakly nonlinear and weakly dispersive flow of a gas in which molecular vibrational relaxation takes place. are derived. The first one governs an excess temperature associated with the thermal mode, and the second one describes variations in vibrational energy. Both quantities refer to non-wave types of gas motion. These variations are caused by the nonlinear transfer of acoustic energy into...
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Low frequency noise and reliability properties of 0.12um CMOS devices with Ta2O5 as gate dielectrics
PublicationW artykule przedstawiono wyniki badań jakości tranzystorów CMOS 0.12um z Ta2O5 użytym jako dielektryk bramki. Przedstawione są charakterystyki statyczne elementów oraz wyniki pomiarów szumów prowadzonych w celu określenia jakości warstwy dielektrycznej Ta2O5, a także wyniki badań przeciążeniowych elementów.
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Fiber optic sensor based on optical frequency domain reflectometry.Optical Fibres and their Applications VIII.
PublicationW pracy przedstawiono wyniki modelowania systemu sensorów światłowodowych wykorzystującego reflektometrię optyczną w dziedzinie częstotliwości. Na podstawie tych wyników zrealizowano quasi-rozłożony sensor temperatury. Zaprezentowano i omówiono wyniki pomiarów.
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Application of the short time Fourier transformation to the continuous frequency method of measurement of electrode impedance
PublicationPrzedstawiona została nowa metoda pomiaru impedancji elektrodowej. Wykorzystuje ona jako pobudzenie niestacjonarny sygnał napięciowy, którego częstotliwość jest liniową funkcją czasu. Zastosowanie transformacji STFT do analizy napięciowego sygnału pobudzenia i odpowiedzi prądowej umożliwia wyznaczenie widma impedancyjnego. Dokładność otrzymywanych wartości impedancji uwarunkowana jest wielkością okna i zastosowanej funkcji analizującej.
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Microfluidically Frequency-Reconfigurable Self-Quadruplexing Antenna Based on Substrate Integrated Square-Cavity
PublicationIn this article, a novel concept of self-quadruplexing tunable antenna (SQTA) enabled by microfluidic channels is investigated. The operating channels are either filled with air or dielectric liquids to enable frequency tunability. The proposed SQTA is implemented on the substrate-integrated square-cavity (SISC). A swastika-shaped slot is milled on the top-surface of the SISC to create four quarter-mode resonators. The resonators...
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An NO2 sensor based on WO3 thin films for automotive applications in the microwave frequency range
PublicationA microwave system dedicated to the detection of nitrogen dioxide in the harsh environment of the Norway highways is proposed. An optimized transmission line type of sensor coated with a tungsten trioxide thin film that changes its electrical properties under NO2 gas exposure is developed. The sensors' response (S) is given in °/GHz and it is calculated based on wideband measurements. The advantage of wideband measurements in comparison...
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Frequency Selective Surface Based MIMO Antenna Array for 5G Millimeter-Wave Applications
PublicationAbstract: In this paper a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2×2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabri-cated on Rogers RT/Duroid high frequency substrate...
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Modelling of Mechanical Behaviour of High-Frequency Piezoelectric Actuators Using Bouc-Wen Model
PublicationThe paper presents the application of a modified, symmetrical Bouc-Wen model to simulate a mechanical behaviour of high-frequency piezoelectric actuators (PAs). In order to identify parameters of the model, a two-step algorithm was utilized. In the first stage, the mechanical parameters were identified by taking into account their bilinear variability and using a square input voltage waveform. In the second step, the hysteresis...
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A spline-based FE approach to modelling of high frequency dynamics of 1-D structures
PublicationIn this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries...
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Multiple output second-generation current conveyor utilizing high frequency output stage
PublicationIn this paper a multiple output second-generation current conveyor (MOCCII) is presented. The main advantage of the proposed general circuit architecture over a typical structure, well known in the literature, is the use of a high passband multiple output current mplifier block instead of cascaded current mirrors. It gives similar frequency responses for all the outputs of the current conveyor and also maintains simplicity of the...
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A new pitch shifter based on complex instantaneous frequency rescaling and direct digital synthesis
PublicationZaproponowano nową metodę zmiany wysokości dźwięku za pośrednictwem skalowania zespolonej częstotliwości chwilowej i na podstawie cyfrowej syntezy bezpośredniej. Zaprezentowano schematy blokowe opracowanych algorytmów. Pracę zilustrowano przykładem syntezy sygnału wywoławczego (''dzwonka'' telefonicznego), gdzie dźwięki poszczególnych nut generowanej melodii uzyskano na podstawie naturalnego sygnału - pojedynczego świergotu o widmie...
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Damage detection in a bolted lap joint using guided waves
PublicationThe paper presents the experimental investigation of guided waves application to the condition assessment of prestressed bolted connections and a concept of new quantitative indicator. The main goal of the research was the analysis of the influence of the contact conditions changes to the characteristics of a propagating disturbance. The experimental tests were carried out for a single bolted lap joint. The excitation and acquisition...
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Emergency condition of the ceramic facade of a residential building
PublicationThe paper presents a description of the technical condition of the ceramic cladding of a residential building, the technical condition of which deteriorated significantly after only a few years of operation. The analysis of the influence of the applied design and working solutions on the façade failure frequency was analyzed. The article presents a conceptual solution to bring the building to the proper technical condition in terms...
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Emergency condition of the ceramic facade of a residential building
PublicationThe paper presents a description of the technical condition of the ceramic cladding of a residential building, the technical condition of which deteriorated significantly after only a few years of operation. The analysis of the influence of the applied design and working solutions on the façade failure frequency was analyzed. The article presents a conceptual solution to bring the building to the proper technical condition in terms...
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Degree of monopoly and market power vs. price flexibility in Polish economy: empirical analysis based on COICOP classification
PublicationResearch background: The issue of price flexibility is crucial in the economy both in the aspect of company theory and its macroeconomic consequences. In a number of publications, the sources of variable price flexibility are linked to the market power of enterprises as well as the market structure that has developed in a given branch. It is difficult to indicate empirical studies that would state clearly whether price flexibility...
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Analysis of circular polarization antenna design trade‐offs using low‐cost EM‐driven multiobjective optimization
PublicationCircular polarization (CP) antennas are vital components of modern communication systems. Their design involves handling several requirements such as low reflection and axial ratio (AR) within the frequency range of interest. Small size is an important criterion for antenna mobility which is normally achieved as a by‐product of performance‐oriented modifications of the structure topology. In this work, multiobjective optimization...
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The AC motor voltage and audible noise waveforms in ship’s electrical drive systems with frequency converters
Open Research DataThe presented dataset is part of research focusing on the impact of the ship's electrical drive systems with frequency converters on vibrations and the level of audible noise on ships.
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INFLUENCE OF BISMUTH CONTENT ON COMPLEX IMMITTANCE CHARACTERISTICS OF PRESSURELESS SINTERED BiNbO4 CERAMICS
PublicationGoal of the present research was to study immittance properties of BiNbO4 ceramics fabricated by the solid state reaction route followed by pressureless sintering. Four sets of samples were examined, namely the one fabricated from the stoichiometric mixture of oxides, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. The immittance properties were studied by impedance spectroscopy. Measurements...
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Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System
PublicationThis paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic...
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Rapid dimension scaling of compact microwave couplers with power split correction
PublicationIn this paper, a technique for rapid re-design ofcompact microwave couplers with respect to operating frequency is discussed. Our methodology involves an inverse surrogate model setup using several reference designs optimized (at the level of equivalent circuit representation of the coupler) for a set of operating frequencies within a range of interest. The surrogate establishes the relationship between the operating frequency...
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Channel Impulse Response Measurements at mmWave Band in Office and Conference Rooms
PublicationIn this paper, the measurements of the channel impulse response at mmWave band in office and conference rooms are described. The central frequency is 27 GHz with a bandwidth of 400 MHz. The description of the used measurement stand and considered environments are presented. The initial analysis of the power delay profile, mean delay, and RMS delay spread allows preliminary conclusions to be drawn that there is a significant impact...
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Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
PublicationIn applications where size and weight of the electric motor are among major design concerns, Permanent Magnet Synchronous Motors (PMSMs) with wide operational speed-range are commonly preferred. Due to limited inverter switching frequency, high-speed operation of a drive results in a low ratio between the switching frequency and the fundamental frequency of motor voltage. Such operating conditions have been recently identified...
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Model-Free Controller Tuning Based on DFT Processing: Application to Induction Motor Drives
PublicationIn this paper, we present a new approach based on discrete Fourier transform (DFT) analysis for controller tuning of the closed-loop system with unknown plant. The DFT analysis is used to process the closed-loop measurements collected online to derive the frequency response of an initial closed-loop system that does not provide a good performance. Based on the closed-loop frequency response data, we propose two methods for tuning PID...
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The Effect of Openings’ Size and Location on Selected Dynamical Properties of Typical Wood Frame Walls
PublicationThe wooden frame constructions are now popular in many developed countries of the world. Many of these locations where such buildings are constructed are exposed to seismic and other shocks which are generated by human activities. This paper discusses the effect of the size and location of openings in the wooden frame walls under dynamic loadings. Natural frequencies of such frames with and without openings have been determined....
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Resonant Frequencies in Microstrip Structure with Omega Medium Substrate
PublicationThe paper presents the research on a rectangular microstrip structure with multilayer substrate containing dielectric and omega medium layers. The effect of pseudochiral medium layer location in the substrate and its thickness on the resonant frequency of the rectangular microstrip structure is investigated. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields. Utilizing the continuity...
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Analiza wpływu błędu częstotliwości próbkowania na sygnały odbierane w systemie LTE
PublicationW artykule dokonano analizy wpływu błędu częstotliwości próbkowania w platformie radia programowalnego na odbierany sygnał LTE (Long Term Evolution).
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Ionospheric scintillations computation using real-time GPS observations
PublicationThe following paper presents the results of quasi-real-time determination of the values of phase scintillations indices at the period of ionospheric disturbances that occurred as a consequence of the Sun flares observed on March 7 and 9, 2012. Double-frequency observations with 1-second measurement interval from the EPN (EUREF Permanent Network) network sites located at high latitudes were used for the analysis. To determine the phase...
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AUTOMATIC OPTIMIZATION OF ADAPTIVE NOTCH FILTER’S FREQUEN CY TRACKING
PublicationEstimation of instantaneous frequency of narrowband com- plex sinusoids is often performed using lightweight algo- rithms called adaptive notch filters. However, to reach high performance, these algorithms require careful tuning. The paper proposes a novel self-tuning layer for a recently intr o- ducedadaptive notch filtering algorithm. Analysis shows th at, under Gaussian random-walk type assumptions, the resultin g solution converges...
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Modeling of free vibrations and resonant frequencies of simply-supported submerged horizontal plate
PublicationA theoretical approach was applied to study the vibration of simple-supported submerged horizontal plate. The derived analytical solution was used to determine natural frequencies for a horizontal plate vibrating in fluid. The investigations were conducted for a very wide range of material density and elasticity modulus covering all materials used in engineering practice. Analysis shows that plate vibration frequency decreases...
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The features of steel surface hardening with high energy heating by high frequency currents and shower cooling
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Numerical Modeling of Steel Surface Hardening in the Process of High Energy Heating by High Frequency Currents
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Efficiency of hybrid equipment combining operations of surface hardening by high frequency currents and abrasive grinding
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High-frequency changes in single-trial visual evoked potentials for unattended stimuli in chronic schizophrenia
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