Phase Noise Evaluation Using the Maximum Time Interval Error and Time Variance for Network Synchronization

Atsushi IMAOKA  Masami KIHARA  

IEICE TRANSACTIONS on Communications   Vol.E77-B   No.12   pp.1564-1569
Publication Date: 1994/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Communication Systems and Transmission Equipment
communication systems and transmission equipment,  network synchronization,  phase noise,  SDH,  pointer operation,  

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Long term phase noises are characterized for network synchronization using two time domain measurement techniques: the Maximum Time Interval Error (MTIE) and Time Variance (TVAR). First, the characteristics of previously measured fiber delay variations are evaluated. The diurnal and annual delay variations and the long term noise feature of random walk phase modulation are well represented by the TVAR technique. The delay variation due to the AU pointer operation is then measured using commercial SDH demultiplexing equipment and compared with the simulation result; the simulation result agrees well with the experimental result. The delay variation in the SDH equipment is simulated using the thermal fiber delay variation measured in the actual network as the input phase of the equipment. It is shown that the SDH equipment sometimes generates delay steps of 617ns, which are larger than the normal pointer operations of 154ns. The long term delay variation, periods over 107s, due to the threshold spacing between the positive and negative stuffing is described. We also show that TVAR is suitable for evaluating the phase noise feature and MTIE can clearly show the peak value of phase noise. The long term phase noises evaluated in this paper are the dominant sources that degrade network synchronous performance. The results of this paper will be useful in designing the equipment synchronous specification.