一种抑制SDH网中指针调整抖动的平滑相位泄漏技术

指针调整会在ＳＤＨ网中引入非常大的低频抖动。通常，在解同步器中需要采用指针泄漏技术来抑制这种抖动以使设备满足ＩＴＵ－Ｔ建议Ｇ．７８３的要求。本文给出了一种新颖的抑制指针调整抖动的方法，这种方法通过一个数字锁相环对指针抖动进行平滑并将平滑相位调相到一个参考信号上，从而避免了１比特或１／Ｎ比特泄中存在的较大的相位量化阶跃。这种方法对指针抖动的泄漏可以近似为一个平滑的过程。对一个ＡＵ－４／Ｅ４实验系统的

Smooth Phase Leaking for the Cancellation of Pointer Adjustment Jitter in SDH Networks

The timing jitter induced by pointer adjustments in SDH Network is much larger than that induced by bit rate justification in PDH. This paper introduces a Novel method for the cancellation of pointer adjustment jitter. In the method, a digital phase locked loop(DPLL) is adoped to smoth the pointer adjustment jitter and modulate the smoothed phase to a reference signal. This method avoids the 1 bit or 1/N bit phase quantizing jumping in normal pointer leaking methods. A desynchronizer for AU 4 to E4(140Mb/s) has been implemented using this method. The testing result shows that the jitter performance is perfect.