On May 20, 2008, experts of the academy and from other organizations were organized by the Bureau of Comprehensive Planning as well as the Basic Bureau of the Chinese Academy of Sciences (CAS) to conduct a review and acceptance on the “Project of Maintenance & Transformation on Microwave Time Transfer System between Lintong and Pucheng”, a project of maintenance & transformation on the mega-scientific device of the CAS undertaken by our center.

The microwave time transfer line between Lintong and Pucheng is responsible for the time synchronization comparison between the clock room of time-keeping standard (Lintong) and the clock room of dissemination control (Pucheng). The analog microwave communication equipment adopted by the former microwave time transfer system is produced in 1970s, thus the components become old, and the fault rate is high, affecting the accuracy of comparison seriously. In Sept., 2006, the project was established after the approval of the CAS to transform technologies of the system.

The time transfer accuracy of the new microwave system is superior to ±10ns, so the stability and reliability are largely improved with the daily stability reaching ± ×10-14. As far as function extension and its convenience for the future performance of research, the system not only transfers and compares the two-way standard time signal, but also transfers two-way data signal, guaranteeing data exchanges and network connection between two places. What’s more, it is able to transfer telephone traffic and video signal, thereby providing necessary technical support for the further implementation of business management and scientific research between Lintong and Pucheng.

The expert group heard the “Summary Report on the Acceptance of Microwave Time Transfer System between Lintong and Pucheng” given by Researcher Dong Shaowu, principal of the project, conducted an on-site inspection on the LintongPucheng microwave system, checked the file materials, and agreed to approve the acceptance review with consensus through inquiries and discussions. According to the expert group, the project realized the overall objective specified in the Assignment Paper, its function and technical indexes were superior to the requirements in the Paper. After transformation, the microwave time transfer system operates stably and reliably with high automation. The digital microwave time transfer system can also function as the research platform for two-way time comparison to carry out relevant researches.