ERROR CONTROL SYSTEM OF PHILIPS COMPACT DISC.

The basic requirement to be imposed on an error control system for digital audio to be used in conjunction with an optical disc as storage medium is, that it should prevent that disc errors will lead to audible clicks during playback. The error control system of Philips compact disc consists of an error correction system or decoder followed by an error concealment unit. Design of the error correction system was based on measured statistics of the disk errors. It was observed that the majority of disk errors are a mixture of predominant random errors and very scarce long bursts. A computer search was carried out to find the convolutional code of shortest constraint length that would meet a given performance specification at a desirable code rate. Implementations made so far prove that a single chip realization of Philips compact disc decoder is very well feasible.