【摘要】 氢原子钟是一种最稳定的 (除极短测量时间间隔之外 )频率标准 ,但是环境温度变化及微波谐振腔老化会引起原子钟输出频率的变化 ,从而导致氢原子钟长期性能变差。为了减小这些影响 ,可借助一种自动调谐器来确保谐振腔的频率始终工作在所需的频率上 ,并采用新的温度控制系统来改善氢原子钟的长期性能。针对这些年来许多氢钟出现的有关问题 ,上海天文台在借鉴国外氢钟实验室经验的基础之上 ,对原有氢钟进行了技术改造 ,并为国家授时中心研制了SOHM - 4型氢原子钟。对该型氢原子钟技术改造特点作了介绍 ,并给出了期望的性能指标及初步的测试结果更多还原

【Abstract】 The hydrogen maser is the generally available frequency standard with the smallest frequency instability for all but the shortest measuring time interval.However,the output frequency of the hydrogen maser changes due to the changes of ambient temperature and the aging of high-Q resonant cavity, which leads to the deterioration of the long-term performance.In order to reduce these influences,an auto-tuning system has been developed to ensure working on the desired frequency for the resonant cavity and a new temperature control system has been designed to improve long-term performance.In view of all the relevant problems in hydrogen masers,the existing hydrogen masers have been improved technically and the hydrogen maser SOHM-4 has been developed based on the experiences of foreign atomic standard laboratories.The characteristics of the improved design,the performance expectation and the primary results of the hydrogen maser SOHM-4 are described in this paper.更多还原