The emergence of integrated broadband cable networks

Abstract

The basic attribute of capacity, now extended by a series of technical innovations, has transformed the crude cable platform into a powerful network capable of supplying advanced broadband telecommunications services to consumers. The author provides an outline of the technical migration that has taken place in cable over the past 10 years. This evolution can be summarized in three steps: fiber, digital, and packets. The first major architectural step occurred in the late 1980s. Single-mode fiber provided a way to replace the string of trunk amplifiers that were the cause of quality and reliability problems in cable. If the composite signal carrying 30-100 TV channels could be delivered into the coaxial network near the home, the trunk amplifiers could be eliminated. The development of analog lasers that could be AM modulated with very broadband signals (and perform at useful signal to noise margins) enabled the addition of fiber to the cable infrastructure. The cable network migrated to the hybrid fiber coax (HFC) structure that uses fiber to deliver signals to neighborhood nodes. From the nodes, the signals are redistributed to homes using the tree and branch coaxial plant previously in place.