Design of digital detection circuit for signal of helium optical pump magnetometer Summary

Abstract

Magnetic field measurement technology is an important method to study physical phenomena related to magnetic field. Magnetic field measurement, especially weak magnetic field measurement, often plays a vital role and has important theoretical significance and engineering value for the research of high-performance magnetic field measurement instruments. The helium optical pump magnetometer is a high-precision magnetic measuring device that uses optical pumping and magnetic resonance to realize magnetic field measurement based on the principle of optical magnetic resonance. It has the advantages of low noise, wide measurement range, and low temperature working environment. It has significant advantages in the field of weak magnetic field measurement and can be widely used in scientific research, national defense construction, industrial production, daily life and other fields. The traditional detection circuit is based on a voltage-controlled oscillator as the core and an analog circuit-based detection system. The modulation signal is used for magnetic field detection. The detection speed is slow, and the modulated signal will superimpose an interfering magnetic field on the probe, affecting the measurement result. This paper designs a digital detection system with DDS technology as the core, which greatly improves the speed of detecting the magnetic field. A new swingswing frequency method is used to avoid the interference of the modulation coil, and a breakthrough in detection speed is achieved, reaching a sampling frequency of 20Hz. To meet the requirements of a system that requires continuous measurement at a faster rate.