A low–order unstructured–mesh approach for computational electromagnetics in the time domain

In the theory of optimal inventory control, a class of com plex Laplace transforms arises for which the theoretist needs to know the form and shape of the time domain equivalents. Several methods have been used to obtain these time domain equivalents. In this paper simulation by analog computer has been used, and a low-order approximation of higher-order transfer functions has been simulated. The accuracy of this low-order approximation has been de termined by use of time domain plots.

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Apodisation in the time domain

Journal de Physique II ◽

10.1051/jp2:1992156 ◽

1992 ◽

Vol 2 (4) ◽

pp. 615-620

Author(s):

G. W. Series

Keyword(s):

Time Domain ◽

The Time Domain

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Impact of Pressboard Aging States on the Time Domain Dielectric Characteristics of Oil-paper Insulation

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms.133.414 ◽

2013 ◽

Vol 133 (7) ◽

pp. 414-415

Author(s):

Shiqiang Wang ◽

Guanjun Zhang

Keyword(s):

Time Domain ◽

Dielectric Characteristics ◽

The Time Domain ◽

Paper Insulation

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JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

Engineering survey ◽

10.25296/1997-8650-2018-12-7-8-76-83 ◽

2018 ◽

Vol 12 (7-8) ◽

pp. 76-83

Author(s):

E. V. KARSHAKOV ◽

J. MOILANEN

Keyword(s):

Fourier Transform ◽

Frequency Domain ◽

Time Domain ◽

Frequency Interval ◽

Single Spectrum ◽

Simultaneous Inversion ◽

Homogeneous Half Space ◽

Time Domain Data ◽

The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

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