SHI Shao-hua1,2，LI Xiao-hui1，HUANG Ning1,2
（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：A high-accuracy frequency source, which is based on the direct digital synthesis（DDS）and is controlled in real-time by the application software run on PC, has been designed and implemented, after the USB（universal serial bus）protocol and DDS were studied and analyzed. In this paper, the hardware structure and the key software architecture are introduced, and the measurement on the performance parameters for this design is given and discussed briefly.
Key words：frequency source；direct digital synthesis（DDS）；universal serial bus（USB）