Distribution and Equalization of Signal on Coaxial Cables Used in 10 Mbit/s Baseband Local Area Networks

A time-domain skin-effect model is used to analyze the tapped coaxial cable. The paper first presents the step response of a coaxial cable with a single tap in the middle. Very good agreement has been obtained between the calculated and the measured results. The model is then applied to the study of a 500 m coaxial cable used in the 10 Mbit/s baseband local area networks. In order to compensate for the skin-effect loss, a simple equalization circuit is designed which can be used in the receivers located anywhere on the cable. Four different cases of tap distribution with up to 100 taps are studied in detail. For each case, two parameters are extracted from the receiver output signal. They are plotted as a function of the cable length to provide a quantitative description of the signal quality.