1,721,206 research outputs found
Algebraic Solution of Time Domain Nonuniform Transmission Lines Equations by 2D Wavelet Transform
No full textn this paper, the numerical solution of nonuniform transmis- sion lines is treated. The method proposed is based on the double wavelet expansion of the multiconductor transmission lines (MTL) equations; the expansion is performed both in the time domain and in the space domain, and the coupled partial differential equations become an algebraic system in the Lyapunov form which is solved by the use of standard techniques. The method has been tested in many cases and has demonstrated to re- quire low CPU time consumption and low memory occupation
Statistical Approach in Complex Circuits by a Wavelet Based Thevenin's Theorem
No full textIn the present work we study the treatment of parameters’ uncertainties in complex circuits, i.e. composed by lumped and distributed elements. These problems are usually treated by the use of Monte Carlo techniques, which are extremely time‐consuming.
A simple procedure for the calculation of the upper and lower limit of the response (i.e. the response bounds) is defined by using the wavelet expansion in time domain of the circuit variables.
When only a part of the circuit is affected by uncertainties we use the Thevenin’s equivalent in the wavelet domain (straightforwardly evaluated) to further reduce the analysis complexity.
The proposed method allows us to directly evaluate the response bounds related to the parameters uncertainties without performing repeated simulations (Monte Carlo method), with a consequent CPU time saving
Field Analysis in Tubular Coilguns by Wavelet Transform
No full textIn this paper, a new method for the field analysis in tubular coilguns by wavelets on the interval and equivalence the- orem is proposed. By adopting the equivalence theorem, the com- putational domain is restricted to the conductive region while ex- panding the space variables by wavelets on the interval. We obtain a storage of the unknowns in a matrix form instead of the usual vector form yielding a savings of memory storage and CPU times. The solution is then obtained by a standard time-stepping method
Improving the Performance of the Boundary Element Method with Time Dependent Fundamental Solutions by the Use of a Wavelet Expansion in the Time Domain
No full textThe object of this paper is a wavelet-based formulation of the boundary element method (BEM) for diffusion problems, characterized by time-dependent fundamental solution. While the BEM is a well known and often used technique, its time-dependent formulation for diffusion problems is very rarely used in practical applications, due to the high computational cost which characterizes it. Here, a new formulation is proposed, which, through the use of the wavelet expansion of the time behaviour of the boundary elements, is characterized by a lower CPU time consumption when compared with the standard BEM diffusion formulation. The problem to be solved is transformed into an algebraic system (of higher dimension) and its solution gives the time domain behaviour of the desired quantities; in this way, the time stepping procedure is avoided. Together with the formulation, the analysis of the computational cost, and two examples are given in the paper
Comments on “Deficiencies in the Way Scattering Parameters Are Taught"
No full textEquivalent representation of multiport circuits by the use of scattering parameters is of fundamental importance, especially in the mi- crowave circuits area. However, in most cases, only a few pages of textbooks are devoted to this topic; based on the author’s experience, the students find it somehow difficult to understand the physical meaning of scattering pa- rameters (while they find other representations, like Z, Y, hybrid, or trans- mission parameters, easy to understand). For this reason, the contribution given by Sadiku (IEEE Trans. Educ., Vol. 46, no. 3, Aug. 2003, pp. 399–404) is very important. Furthermore, in Sadiku’s paper, three nontrivial exam- ples are reported, through which the students can gain understanding of this fundamental tool. In two of the three examples, some points are un- clear; this correspondence analyzes this lack of clarity
Characterization of a Wireless Power Transfer System as a Channel for Power Line Communications
No full textWireless power transfer (WPT) is becoming an attractive technology for different applications, from domestic to the automotive environment. At the same time Smart Grids are nowadays penetrating our daily habits and in the future the information exchange between different devices being part of the same power grid will be a common feature. WPT somehow “breaks” the cabled connection (with well known advantages) also interrupting the possibility of transmitting data on power cables. This study is the first attempt to embed Power Line Communication (PLC) in a WPT systems
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