Detection and estimation of a fault on coaxial cable via time-frequency domain reflectometry

The time-frequency domain reflectometry (TFDR) is a newly proposed method to detect and locate a fault in a coaxial cable. The purpose of this paper is to discuss the usefulness and effectiveness of the TFDR for detection and localization of a fault. The traditional reflectometry methods can be chategorized in either the time domain or frequency domain only; however, the TFDR utilizes time and frequency information of a transient signal to detect and locate the fault. The TFDR approach described in this paper is summarized by the design of a time-frequency reference signal and the post-processing of the reference and reflected signals. The design and processing are completely based on joint time-frequency analysis to deal with time and frequency localized information. With the aid of signal generation and acquisition instruments, the TFDR algorithm has been verified for a real world coaxial cable (RG 142 type) for different states of the fault. Also the TFDR algorithm is compared with the traditional TDR. On the basis of the experimental results provided in this paper, TFDR locates the fault with smaller error than time domain reflectometry.