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The efficient computation of interactions in charged particle systems is possible based on the well known Ewald summation formulas and the fast Fourier transform for nonequispaced data (NFFT). The resulting method is known as the particle-particle NFFT (P2NFFT) and has recently been generalized in order to consider electrostatic systems containing charges as well as dipole particles. The software...
This project used a ECG simulator built upon the Fourier series principle to study the patterns of normal and abnormal (defined as both above and below normal ranges) heart beats and other important ECG parameters for children of differing age groups. Across age groups with normal and abnormal settings, the heart rate is shown as positively correlated with R wave peaks, and inversely correlated with...
We introduce two generalizations of the exponential function and, hence, two generalizations of the Fourier transform and series. Each generalization depends on a real, nonnegative parameter less than or equal to one, but reduces to the standard exponential function when the parameter is equal to one. For this reason, the corresponding transforms are called fractional Fourier transforms. In this talk...
The Fourier modal method in Cartesian coordinates uses Fourier series as the expansion basis [1]. This leads to periodic boundary conditions, which is advantageous for periodic structures like photonic crystals. However, for modelling open geometries periodic boundary conditions leads to parasitic reflections from the leaky modes into the computational domain. This can be overcome by using absorbing...
The Hilbert transform plays an important role in many different applications. Especially in the area of detection and estimation it is closely related to the calculation of the spectral factorization. Generally, it is not possible to calculate the Hilbert transform in closed form. Therefore approximation methods are applied. This paper studies the stability of a general class of approximation algorithms...
Restrictions of double Fourier series implementation for modulated signal representation are considered. A general extension of double Fourier series for modulated signal with arbitrary modulation is proposed. The Fourier series premodulation with width and position functions is considered. The premodulation function properties are analyzed. Double Fourier series implementation on a program modulated...
A results of numerical analysis RCWA diffraction by metal gratings under plasmon resonance are presented. Numerical experiments show low convergence of traditional RCWA for such types of the resonances of electromagnetic field. Modified RCWA for studying resonance diffraction phenomena on metal gratings was proposed. Dielectric permittivity functional dependence of grating as complex Fourier series...
Existing PWM analysis techniques are mathematically intensive processes and are not directly compatible with the analysis of methods that feature variations in the switching frequency and/or complex commands. This paper presents a powerful and computationally efficient analysis technique of single phase and multi-phase systems that is suitable for any method of PWM, including standard, fixed switching...
This work addresses an efficient and highly reliable Noise-Vibration-Harshness simulation and analysis framework for electrical induction drives in E-mobility applications. Based on a combined nonlinear analytic and Finite-Element modeling structure in spatial frequency space the entire operational Noise-Vibration-Harshness-simulation is embedded in one simulation environment and can be performed...
The paper presents examples of the results of experimental research concerning the influence of input signal RMS on the measurement error of harmonics using selected power quality analyzers. The experiments were carried out in a designed and prepared measuring system. The system makes it possible to set selected testing signals. In the case considered, the input signals were, respectively, sinusoidal...
Feedforward control is widely used in industrial robot as a valid control method. High speed motion will bring the vibration for robot with flexible joints, which will affect the dynamic performance of robot. The residual vibration character is analyzed for palletizing robot using feedforward control method in this paper. Considering the vibration suppression constraints polynomials fitting method...
A time domain signal tracking algorithm is proposed to estimate the frequency of a chirp-type global navigation satellite system (GNSS) interference. The unknown interference frequency of GNSS in the received signal can be estimated by using the properties of the trigonometrical functions, but the thus-obtained value can have a lot of error caused by measurement noise and by the frequency change of...
Although the Hilbert transform plays an important role in many different applications, it is usually impossible to calculate it exactly in closed form. Therefore approximation methods are applied to determine numerically the Hilbert transform. The present paper studies a general class of approximation methods on signal spaces of finite Dirichlet energy. This class is characterized by two natural axioms,...
Inductive Power Transfer (IPT) system makes use of high frequency inverter and resonant compensation network to transmit power without any electric contact, which makes power transfer more convenient and safer. IPT system is a high order and nonlinear system, modeling and analysis of such a system is complicated because its state variables like inductor currents and capacitor voltages present rapid...
Steady state analysis is fundamental to give the first observation in circuit design. Buck converter driven by switching has complexity that the circuit topology changes as switching. In this paper a steady state analysis of buck converter is proposed which allows the exact calculation of steady state response. Proposed method uses Fourier series and a recovery function to express steady state output...
In this work, using the numerical analysis of the diffraction TM-polarized optical waves by metal gratings under resonance of the electromagnetic field was presented. Modified RCWA method has been proposed. Notably, Toeplitz matrices were modified in the system of differential equations. These matrices are formed on base of complex series of the periodic function of grating's dielectric permittivity...
Taylor's 1952 Fourier series for a uniform circular array's pattern here yields simple steering, with minimal distortion, by applying a phase ramp to the weights' DFT coefficients rather than to the weights themselves as for a linear array. Computational examples include steering a simple monopulse difference beam created as the difference between steered beams.
This paper presents a procedure for calculating efficiently the frequency perturbations for circular array of coupled cylindrical dipole antenna. This is commonly done through subsequent application of the algorithm at different values of frequency. A novel technique is developed where the coupled integral equations for the circular array is solved using the method of moments at a single frequency...
This paper presents a newly developed laboratory paradigm for the laboratory component of signals and systems courses. It involves the implementation of signals and systems algorithms that are written in MATLAB on smartphones using their ARM processors. This smartphone-based approach enables an anywhere-anytime environment for students to conduct signals and systems experiments. The steps involved...
In this paper we analyze the convergence behavior of a sampling based system approximation process, where the time variable is in the argument of the signal and not in the argument of the bandlimited impulse response. We consider the Paley-Wiener space PWπ2 of bandlimited signals with finite energy and stable linear time-invariant (LTI) systems, and show that there are signals and systems such that...
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