The time and frequency system of the Tianma 65 m radio telescope

A time and frequency system is a critical component of Very Long Baseline Interferometry (VLBI) stations, providing stable and reliable standards that directly impact data processing quality. At the Tianma 65 m radio telescope (TMRT), this system has been meticulously designed to ensure long-term reliability and high performance. It incorporates high-performance hydrogen atomic clocks, high-precision time standards, automatic signal switching, and robust system software. This comprehensive approach has enabled the system to achieve long-term reliable operation, successfully supporting both major national engineering tasks and daily scientific observations. The effectiveness of the system is evidenced by its consistent delivery of the precision and stability required for radio astronomy. This article provides an in-depth exploration of the design and operation of the time and frequency system at the Tianma 65 m telescope, examining various aspects of its architecture, implementation, and performance. By sharing these insights, we aim to contribute knowledge that could benefit similar systems at other VLBI stations, greatly advancing radio astronomy infrastructure.