NIM铯原子喷泉钟微波频率综合器的研制

The Design of Microwave Synthesizer for Cesium Atomic Fountain Clock of NIM

为了研制NIM5铯原子喷泉钟系统，在PLL锁相环路、100MHz干涉开关和倍频链路等技术的基础上，提出了微波综合器的设计和实现方案。介绍了微波综合器设计中的关键技术：利用氢钟提高综合器的长期稳定度、采用微波干涉开关抑制微波泄露频移，以及通过DDS提高综合器的准确度。测试结果表明，该微波综合器在谱纯度、相位噪声和稳定度等指标上均满足设计要求，具有模块化程度高、结构简单的特点，并已成功应用于NIM5铯原子喷泉钟系统中。

In order to develop NIM 5, the laser-cooling cesium fountain primary frequency standard in operation at NIM, China, the design and implementation of the microwave frequency synthesizer used in NIM 5 are given according to the basement of some techniques, such as PLL, 100 MHz interference switch and multiplier chain. The key techniques are described, such as using H-maser to improve the long stability of microwave synthesizer, using electronic interference switch to suppress microwave leakage, and improving the microwave synthesizer＇s accuracy through DDS. The measurement results indicate that the main metrological features（spectral purity, phase noise, and the long term phase stability） of this microwave synthesizer meet the design requirements. And the structure of this synthesizer is simple and the degree of modularization is high. The microwave synthesizer has successfully been used in NIM 5 fountain clock.