Measurement and causal modelling of twisted pair copper cables

Abstract

The modelling of twisted pair copper cables has been under investigation in recent years with the emergence of several forms of digital subscriber line broadband access technology including G.fast. Designers of these communication systems implement these models to prototype early system architectures as well as simulate feasibility trials on the existing subscriber loop infrastructure. Previous attempts at modelling these cables have been limited because of the challenges associated with acquiring physical measurement and the inaccuracies of simulators to model effects such as the skin effect, which is significant when using these cables in high‐speed systems. These previous modelling attempts employed empirical formulas to match the measured primary transmission line parameters (RLCG) of the cables and generally failed to meet the Kramer–Kronig causality relationships. This paper presents a measurement setup for the electrical properties of twisted pair copper cables as well as a realizable RLCG model for the cables. This model is based on electromagnetic theory considering the model causality, the skin effect, and the twisting of the cable.