frame alignment procedure in digital transmission systems

every digital transmission system requires frame alignment. it is necessary to identify the varius signal componets and to bring receiver into phase with respect to the transmission format so that the digits can be properly assembled for demultiplexing. fast and reliable frame alignmant is important, and therefore has been a subject for study. this paper a comprehensive analysis of frame alignment procedure used for time division multiplex equiment complying with european standards (which is used in iran and many other countries). the study complements the work of others on frame alignment by presenting a more simplified method for understanding frame alignment procedure. the approach derives the probability generating function of frame alignment procedure from the generalized state transition diagram of sitter. the probability generating function is then used to estimate the average and variance of the timing parameters. the principal transition times (out - of- frame detection time, maximum average reframe time, false in - frame time and misframe time) is used as a performance criteria for optimization of parameters. the effect of design criteria on various timing parameters is presented graphically and a realistic example is considered.