Abstract: PLL is the key technology of slave-node clocks applied in master-slave synchronization network, while the performance of the PLL isone of the most critical factors to ensure network synchronization. The PLL based on ‘single-loop’ theory has been universally adopted. Due to technology limitation, such design has to face the problems of steadiness and preciseness. Inthis article, a new solution, ‘Dual-Loop’ Intelligent Loosely Coupled PLL, is proposed. The design ideas and the theories are given, and the loop parametersare analyzed. Comparing to the ‘single-loop’ PLL, the design proposed in this article is proved to be able to improve the performance greatly in system steadiness and preciseness.

Key words: network synchronization, master-slave synchronization, clock, loosely coupled PLL