FAN Zhan-you1, FAN Xi-qing1, 2, ZHANG Shou-gang1, 3

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

2. Graduate University of Chinese Academy of Science, Beijing 100039, China;

3. Key Laboratory of Time and Frequency Primary Standards, Chinese Academy of Sciences, Xi’an 710600, China)

Abstract:In order to meet the needs of some important research projects such as precise time measurement and high-performance on-board atomic clocks, a DDS(direct digital synthesis) random frequency synthesizer, which is composed mainly of AD9956 chip and 8 bit high-performance SCM(single chip microprocessor), has been developed. Based on the analyses of the basic principles and characteristics of DDS, the authors made a detailed description of the design of the random frequency synthesizer in both of hardware and software in detail, and the authors also introduced a dedicated application software which is used for computer to control the synthesizer. The experiments show that the frequency synthesizer meets the requirements of the advanced researches and has played an active role in promoting the completion of research project.

Key words: DDS(direct digital synthesis); frequency synthesis; frequency (or phase) control resolution