XIANG Yu1,2，HUA Yu1，WU Hai-tao1

（1. National Time Service Center, Chinese Academy of Sciences, Xi’an, Shaanxi 710600, China;

 2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China）

Abstract: The basic principle and conventional implementation methods for the disciplined clock system are introduced in this paper. An implementing scheme based on digital phase locked loop（PLL）is designed following an analysis of the shortage of the generic implementing method of the GPS disciplined clock system, and a new GPS disciplined clock system is developed based on the scheme. The result of actual measure shows that the stability of local 1PPS out-put obtained by using the new method is better than that obtained by using the conventional one.

Key words: disciplined clock；phase lock loop；GPS