LIU Ya1,2，LI Xiao-hui1,，WANG Wen-li1

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

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

Abstract: A frequency standard comparison platform based on beat-frequency technique has been designed to evaluate the difference of performance between the periodic frequency measurement with counter and the digital beat-frequency signals processing with computer, the fundamental of measurement and realization of the two sets of systems are analyzed. The factors which result in the high performance of the digital beat frequency measurement system are expounded. The comprehensive performances of the two sets of systems have been tested and analyzed. The stability of the measured values obtained with the counter method is (Allan Deviation,), whereas the stability of the measured values obtained with the digital method is , almost two orders better than the former.

Key words: frequency standard comparison; beat-frequency; digital frequency measurement; virtual instrument