TABLE OF CONTENTS PETER HUCKETT and GEOFF THOW
Hewlett-Packard Ltd.
Evolving integrated digital networks (IDNs) and integrated services digital networks (ISDNs) require definition and analysis of error performance of digital line sections comprising the network. This chapter describes some of the methods currently in use, development of international standards, and appropriate measurement equipment for digital muldex (multiplex-demultiplex), digital radio, and digital line systems (over copper or glass).
The basic measure of performance of any digital transmission system is the probability of any transmitted bit being received in error. In general, these errors occur in the regenerative repeaters of digital line sections (be they cable, fiber or radio links), which are used to achieve the most significant advantage of digital transmission over analog transmission, namely, distortion in the service carried almost independently of distance. This can be achieved only if the spacing of the regenerators and other contributing sources of error are controlled in such a way to give a low enough overall error rate [CCITT, 5.1]. For example, line-induced errors may be modified or magnified by the operation of terminal equipment such as descramblers. Several other parameters of the system may contribute to errors for example, signal level, noise level, and timing jitter but the most important criterion on which a system is judged is its error performance and the effect of those errors on the service being carried. The implementation of an ISDN, where the integrated functions of switching, terminals, and transmission of an IDN are used...
