The Dick effect is an important factor limiting the frequency stability of sequentially-operating atomic frequency standards. Here we study the impact of the Dick effect in the integrating sphere cold atom clock （IS...The Dick effect is an important factor limiting the frequency stability of sequentially-operating atomic frequency standards. Here we study the impact of the Dick effect in the integrating sphere cold atom clock （ISCAC）. To reduce the impact of the Dick effect, a 5 MHz local oscillator with ultra-low phase noise is selected and a new microwave synthesizer is built in-house. Consequently, the phase noise of microwave signal is optimized. The contribution of the Dick effect is reduced to 2.5× 10^-13τ-1/2 （3- is the integrating time）. The frequency stability of 4.6 × 10-13τ-1/2 is achieved. The development of this optimization can promote the space applications of the compact ISCA C.展开更多
综合监控系统已日渐成为城市轨道交通自动化系统中的一种基本系统。为了保证综合监控系统可靠安全地工作,可靠性、可用性、可维修性、安全性(Reliability、Availability、Maintainability and Safety,简为RAMS)管理规范已逐渐被应用到...综合监控系统已日渐成为城市轨道交通自动化系统中的一种基本系统。为了保证综合监控系统可靠安全地工作,可靠性、可用性、可维修性、安全性(Reliability、Availability、Maintainability and Safety,简为RAMS)管理规范已逐渐被应用到城市轨道交通的自动化控制领域中。介绍了城市轨道交通综合监控系统的RAMS管理方法,详细分析了综合监控系统项目的RAMS组织结构、RAM分析方法、危害性分析方法及故障报告、分析和纠正措施系统等内容。指出在实际的综合监控系统项目中,需根据项目的具体特点,在RAMS规范的指导下开展有效的工作,才能真正提高项目的RAMS水平。展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11604353the Youth Innovation Promotion Association of Chinese Academy of Sciences
文摘The Dick effect is an important factor limiting the frequency stability of sequentially-operating atomic frequency standards. Here we study the impact of the Dick effect in the integrating sphere cold atom clock （ISCAC）. To reduce the impact of the Dick effect, a 5 MHz local oscillator with ultra-low phase noise is selected and a new microwave synthesizer is built in-house. Consequently, the phase noise of microwave signal is optimized. The contribution of the Dick effect is reduced to 2.5× 10^-13τ-1/2 （3- is the integrating time）. The frequency stability of 4.6 × 10-13τ-1/2 is achieved. The development of this optimization can promote the space applications of the compact ISCA C.
文摘综合监控系统已日渐成为城市轨道交通自动化系统中的一种基本系统。为了保证综合监控系统可靠安全地工作,可靠性、可用性、可维修性、安全性(Reliability、Availability、Maintainability and Safety,简为RAMS)管理规范已逐渐被应用到城市轨道交通的自动化控制领域中。介绍了城市轨道交通综合监控系统的RAMS管理方法,详细分析了综合监控系统项目的RAMS组织结构、RAM分析方法、危害性分析方法及故障报告、分析和纠正措施系统等内容。指出在实际的综合监控系统项目中,需根据项目的具体特点,在RAMS规范的指导下开展有效的工作,才能真正提高项目的RAMS水平。
