Research On Signal Detection System Of Self-excited Cesium Optical Pump Magnetometer

Precision magnetic field measurement has become one of the key research directions at home and abroad.Optical pump magnetometer plays an important role in magnetic field measurement.Compared with other magnetometers,self-excited cesium optical pump magnetometer has the advantages of small volume,simple structure and stable performance,so it has high research value.Among them,the phase control circuit,high resolution and high response speed of the La Moore frequency detection circuit is self-excited cesium optical pump magnetometer signal detection system key technology,there are still technical difficulties yet to be resolved.To this end,this paper track the advanced optical pump magnetometer technology for these two major circuits to carry out research work.Firstly,the working principle of the self-excited cesium optical pump magnetometer is introduced.The cesium optical pump magnetometer is the theoretical basis for the generation of Zeeman splitting in the external magnetic field,and the instrument is transformed into the magnetic field measurement by the measurement of Ramol frequency.Next,we study the phase condition of the self-excited oscillation and the Ramall frequency.Self-excited cesium optical pump magnetometers need to generate self-oscillating oscillations like oscillators themselves,so they need to meet the phase conditions of self-excited oscillations.In this paper,the phase shift circuit is designed to realize the phase shift in the range of 30 kHz to 350 kHz with the angle in the range of 180 degrees,which solves the influence of the signal frequency on the phase.In addition,the system needs to be in the wide frequency range of cesium atomic magnetic moment around the constant magnetic field with a constant frequency of Ramallor high precision measurement.In this paper,a full-synchronous frequency measurement method and FPGA technology to achieve high-resolution frequency measurement circuit,in order to achieve a high-resolution magnetic field measurement.Finally,the feasibility of voltage-controlled phase-shifting circuit and frequency measurement circuit is verified by experiments,which satisfies the requirements of magnetic field measurement.