xample, in contrast to the above well behaved applica- CCITT (1988c) Recommendation G.703, General Aspects of Inter- tion, systems which have to acquire alignment frequently, particu- faces, Blue Books, Geneva. larly if from a random starting position, will usually require longer Choi, D.W. (1990) Frame Alignment in a Digital Carrier System FAWs. On the other hand, long FAWs are more liable to experience a Tutorial, IEEE Communications Magazine, pp. 47-54 (Fe- transmission errors. Thus, the word choice and the alignment strategy are closely linked. For example, in the presence of trans- bruary). Dawson, P.A. and Kitchen J.A. (1986) TAT-8 Supervisory System, mission errors it may be worthwhile to accept window positions that demonstrate a close but not necessarily exact match to the expected British Telecom Engineering Journal, 5, (July). FAW. The implications of this and other variations on the basic Duc, N.Q. and Smith B.M. (1977) Line Coding for Digital Data alignment approach described above are to be found in the lit- Transmission, Australia Telecommunications Research Jour- erature. nal, 11, pp. 14-27. Fair, I.J., Grover, W.D., Krzymien, W.A. and MacDonald, R.I. 28.5.5 Further reading (1991) Guided Scrambling: A New Line Coding Technique for High Bit Rate Fibre Optic Transmission Systems, IEEE Trans- A good introduction to frame alignment is to be found in (Bylanski actions on Communications, 39, pp. 289-297 (February). Franks, L.E. (1968) Further Results on Nyquist's Problem in Pulse and Ingram, 1986) and in several more recent books which refer to them and adopt a similar approach. Some of the subtleties of the Transmission, IEEE Transactions on Communications, 16, pp. 337-340. alignment process with examples based on CCITT specifications are discussed in (Jones and Zhu, 1985), a similar method of analysis Franks, L.E. and Bubrowski J.P. (1974) Statistical Properties of (using probability generating functions) is adopted in a tutorial Timing Jitter in a PAM Timing Recovery System, IEEE Trans- article (Choi