Simulation of clock noise and AU-4 pointer action in SDH equipment

One of the most important open issues in standard bodies dealing with synchronization of SDH networks is a better understanding of the impact of phase and frequency instabilities in synchronous equipment clocks (SECs) on the statistics of pointer adjustments. In this paper, a flexible simulator of clock phase noise and of AU-4 pointer action is described. This simulator was designed with the aim of investigating how different spectra of SEC noise do impact on the statistics of AU-4 pointer adjustments. In particular, some results of simulations of different kinds of SEC noise obeying the power-law model are provided. Moreover, results of simulation of SEC noise fitting the ITU-T and ETSI standard mask specifying wander tolerance in terms of time deviation are reported