CPT磁力仪是一种用于微弱磁场测量的新型高灵敏度原子光学磁力仪, 针对 CPT磁力仪垂直腔面发射激光器电流调制需要产生低相位噪声调制信号, 提出了一种基于锁相环频率合成器的方案。该方案从 CPT磁力仪的基本原理出发, 分析了 CPT磁力仪对调制信号的频率要求, 根据锁相环频率合成基本原理, 采用锁相环仿真软件 ADIsimPLL完成了频率合成器中关键模块参数的确定, 产生了高精度、低相噪以及杂散性好的 3.4 GHz频率信号, 并对系统性能进行了仿真分析。经仿真测试表明, 锁相效果良好, 性能可靠, 可以满足 CPT磁力仪的研制。

Coherent population trapping (CPT) magnetometer is a new high sensitive atomic optical magneometer for weak magnetic field measurement. According to low phase noise modulated signal requirements in the process of current modulation of vertical cavity surface emitting lasers (VCSEL) of the magnetometer, a scheme based on phase locked loop (PLL) frequency synthesizer is presented. On the basis of basic principles of CPT magnetometer, frequency requirements of modulated signal for CPT magnetometers are analyzed. According to basic principles of frequency synthesis of PLL, key module parameters in frequency synthesizers are determined by ADIsimPLL software. A 3.4 GHz frequency signal with high precision, low phase noise and good spurs is generated and simulation analysis is performed to the system. Simulation results shows that the system has good phase-locking effect, reliable performance and can meet the research of CPT magnetometer.