Analysis of output slave clock stability in SDH systems in terms of percentile MRTIE(τ)
✍ Scribed by Vittorio Ricchiuti; Pietro Ciammaichella
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 114 KB
- Volume
- 11
- Category
- Article
- ISSN
- 1074-5351
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✦ Synopsis
The 'maximum (relative) time interval error' (MRTIE()) is one of the parameters most used by international standardization bodies to characterize the stability of the clocks in modern SDH synchronization networks. Besides the original definition of MRTIE(), ITU-T has introduced a new MRTIE() definition of percentile character. This new definition allows linking of the MRTIE() parameter to the stochastic noise processes affecting the clocks in synchronization networks.
In this paper, after a brief discussion about the original and percentile definitions of MRTIE(), the study focuses on the output stability of a slave clock based on a phase-locked loop (PLL) system. A PLL with internal phase noise sources and fixed bandwidth value is considered. The output slave clock stability is studied when there is a step change in the phase of the PLL reference signal. The need to consider the MRTIE() parameter not only as a simple measure of wander (slow phase fluctuations) but also as a measure of fast phase fluctuations (jitter) on the clocks is emphasized, in spite of the latest ITU-T recommendations and ETSI standards.