Abstract
This paper reports a method to detect the location where the characteristic impedance changes partially in the long co-axial cable.
By assuming the cable as the series of uniform sections, the reflected wave for the pulsate voltage applied at the end of the cable is represented with ARMA model with the coefficient of the voltage reflection factor between two adjacent sections.
In the case of low reflection factor, it is possible to detect the location of impedance unbalance point by estimating the voltage reflection factor with Kalman filter application.
In our experiment, we could detect the location of impedance unbalance point within ±5m accuracy at the distance of 2Km from the end of the cable.
