Analytical description of chromatic dispersion effect on signal propagation in the time domain

2017 ◽  
Author(s):  
Mikhail Meltenisov ◽  
Aleksandr Matukhin
Keyword(s):  
Time Domain ◽  
Chromatic Dispersion ◽  
Analytical Description ◽  
Signal Propagation ◽  
Dispersion Effect ◽  
The Time Domain

Spectrally efficient optical CDMA system based on chromatic dispersion for phase coding of individual spectral lines in the time domain

2009 ◽  
Author(s):  
Santiago Tainta ◽  
Waldimar Amaya ◽  
Maria J. Erro ◽  
Maria J. Garde ◽  
Raimundo García-Olcina ◽  
...  
Keyword(s):  
Time Domain ◽  
Chromatic Dispersion ◽  
Spectral Lines ◽  
Optical Cdma ◽  
Cdma System ◽  
Phase Coding ◽  
Spectrally Efficient ◽  
The Time Domain

scholarly journals Efficient reconstruction of dispersive dielectric profiles using time domain reflectometry (TDR)

2005 ◽  
Vol 2 (4) ◽  
pp. 1449-1502 ◽  
Author(s):  
P. Leidenberger ◽  
B. Oswald ◽  
K. Roth
Keyword(s):  
Inverse Problem ◽  
Global Optimization ◽  
Time Domain ◽  
Signal Propagation ◽  
Dielectric Materials ◽  
Time Domain Reflectometry ◽  
Domain Model ◽  
Parallel Circuit ◽  
The Time Domain ◽  
Analytical Expressions

Abstract. We present a numerical model for time domain reflectometry (TDR) signal propagation in dispersive dielectric materials. The numerical probe model is terminated with a parallel circuit, consisting of an ohmic resistor and an ideal capacitance. We derive analytical expressions for the capacitance, the inductance and the conductance of three-wire probes. We couple the time domain model with global optimization in order to reconstruct water content profiles from TDR traces. For efficiently solving the inverse problem we use genetic algorithms combined with a hierarchical parameterization. We investigate the performance of the method by reconstructing synthetically generated profiles. The algorithm is then applied to retrieve dielectric profiles from TDR traces measured in the field. We succeed in reconstructing dielectric and ohmic profiles where conventional methods, based on travel time extraction, fail.

scholarly journals Efficient reconstruction of dispersive dielectric profiles using time domain reflectometry (TDR)

2006 ◽  
Vol 10 (2) ◽  
pp. 209-232 ◽  
Author(s):  
P. Leidenberger ◽  
B. Oswald ◽  
K. Roth
Keyword(s):  
Inverse Problem ◽  
Global Optimization ◽  
Time Domain ◽  
Signal Propagation ◽  
Dielectric Materials ◽  
Time Domain Reflectometry ◽  
Domain Model ◽  
Analytical Approximations ◽  
Parallel Circuit ◽  
The Time Domain

Abstract. We present a numerical model for time domain reflectometry (TDR) signal propagation in dispersive dielectric materials. The numerical probe model is terminated with a parallel circuit, consisting of an ohmic resistor and an ideal capacitance. We derive analytical approximations for the capacitance, the inductance and the conductance of three-wire probes. We couple the time domain model with global optimization in order to reconstruct water content profiles from TDR traces. For efficiently solving the inverse problem we use genetic algorithms combined with a hierarchical parameterization. We investigate the performance of the method by reconstructing synthetically generated profiles. The algorithm is then applied to retrieve dielectric profiles from TDR traces measured in the field. We succeed in reconstructing dielectric and ohmic profiles where conventional methods, based on travel time extraction, fail.

Apodisation in the time domain

1992 ◽  
Vol 2 (4) ◽  
pp. 615-620
Author(s):  
G. W. Series
Keyword(s):  
Time Domain ◽  
The Time Domain

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

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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