适合于SDH设备的从钟的定时特性分析

Timing Characteristics Analysis of SDH Equipment Slave Clocks

适合于ＳＤＨ设备的从钟，是ＳＤＨ网络所特有的从时钟。文中对Ｇ．８１３从钟的定时特性作了详尽分析。首先，介绍了定时信号的数学模型，然后给出了表征频率和时间稳定性参数的定义和性质，并对其进行了时域和频域分析。在此基础上建立了Ｇ．８１３从钟的噪声模型。最后对ＩＴＵ－Ｔ建议Ｇ．８１３给出的定时特性规范中所存在的若干问题进行了讨论，提出了自己的见解。

The slave clock adapted to SDH equipments, as well as the G. 813clock, is the special clock of SDH network. This article analyses the timing characteristics of the G. 813 clock in detail. Firstly,the paper introduces the mathematical model of timing singal. The definition and characteristics of parameters which indicate the stability of frequency and time are given. And the analysis in frequency and time domain is made. Based on these,the noise model of G. 813 clock is built. Finally, the several questions about timing charateristic standard given in ITU-T Rec. G. 813 are discussed. The unique opinions are given.