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Abstract-Time-reversal (TR) invariance of the wave equation in lossless transmission line (TL) is here introduced as an improvement for fault-detection techniques in wire networks. This new approach is applied to reflectometry in wire diagnosis. To test the efficiency of this method, the reverse time algorithm simulated with FDTD (Finite Difference Time Domain) is developed in a one dimension space. It uses a new signal processing and an adapted signal to the wire under test for diagnosing the fault in the wire. In addition, the interest of the convolution product between the incident signal and the output signal from this reverse time method will be also shown and applied in this paper. Through numerical simulations and experimental results measured on coaxial cable, the benefits of this method have been illustrated.

A new post-processing approach which aims at reducing the dispersion effect of the wave travelling inside a waveguide is presented. The main objective is to improve the time domain reflectometry measurements performed over long-distance cables, relative to the wavelength λ. A real-case scenario is presented so that the gain of this method can be appreciated.Introduction: Cables are present in almost all modern systems. These cables are subject to several electrical, chemical and mechanical stresses. Depending on the application area, such degradation can lead to hard faults (short or open circuits) and therefore catastrophic consequences [1]. Reflectometry methods are commonly used for assessing transmission lines [2]. This Letter overcomes reflectometry's limitations by proposing a signal processing technique based on dynamic crosscorrelation for the detection and the localisation of faults over longdistance cables.

Abstract-This paper investigates the effects of aging on electrical cable characteristics and proposes a new method for detecting and characterizing cable aging (i.e. homogeneous slow degradation) based on time reversal. In case of a global cable aging, the commonly used methods such as reflectometry provide non-relevant or inaccurate information. Through theoretical study and numerical simulations, the benefits of this new method called Time Reversal Reflectometry (TRR) are presented. TRR is experimentally shown to be successful for the detection and quantification of cable aging.