Characterization and modeling of cables for high-speed datacommunications applications

摘要

Designers of data communications systems continue to push thelimits of copper cable to achieve higher speeds and longer cablelengths. At the same time, shortened product schedules due tocompetition often prevent the use of prototyping in early systemarchitecture. These developments mandate the use of simulation in earlysystem feasibility and design. Simulation has been used in the design ofVLSI ICs for many years, and has been adopted at the card and boardlevel in recent years as the speed of digital systems increases.However, modeling of cables has not been widespread due to thedifficulty in obtaining the physical data necessary for the task, aswell as the inadequacy of many simulators to properly simulate the skinand other effects encountered when using cables in high-speed systems.This paper will present hardware measurement data for some types ofshielded parallel and twisted pair cable typically used for theinterconnection of high-speed digital systems, and outline some of theproblems encountered in the electrical characterization and modeling ofthose cables. Selected simulation models will be presented, withcomparisons of the measured and simulated results obtained using thosemodels