By John T. Griffin, Jerroid Communications
Digital carriage of data via CATV networks is becoming more prevalent with each passing year. Digital radio services are presently being offered by numerous cable operators. Digital compression of video is just over the horizon, am other data services will likely follow. Although these digital delivery systems do not exhibit the impairments of their analog counterparts, bit errors may cause catastrophic distortions. Forward error correction is one aspect of a solution to this problem.
This paper introduces the CATV system engineer to the concepts of forward error correction, am discusses its benefits, complexity, am limitations. It also touches on the interdependence of forward error correction with channel equalization am efficient modulation. Several important concepts, such as coding gain, are discussed in detail.