Impedance Reconstruction of Airborne Coaxial Cable for Non-Uniformity Test

Abstract

Characteristic impedance is the key characteristic parameter to measure the impedance uniformity of coaxial cable. In the traditional impedance test method, the multiple reflection phenomenon caused by the internal impedance discontinuity point of the cable is one of the main causes of the cable impedance test error. Although a variety of methods have been used in the past and a lossless cable impedance reconstruction algorithm has been designed to quantify multiple reflection components, most of the calculation processes are complex and ignore the influence of cable attenuation on impedance testing, so that the test results still have large errors. Therefore, this article effectively compensates the signal transmission loss by establishing the cable attenuation characteristic model, and further optimizes the lossless cable impedance reconstruction algorithm. Combined with the attenuation characteristic model, the attenuation component is introduced in the multiple reflection calculation, and a new lossy cable impedance reconstruction algorithm is proposed. The frequency domain simulation verification is carried out in advanced design system software, and the vector network analyzer is used for experimental verification. The results show that the lossy reconstruction algorithm can obtain more accurate impedance test values, and the error is less than 2.5%.