Study on the Application of multiple auto-correlation in Rapid tuning of Overhauser Magnetometer

In order to solve the problem of slow tuning speed and easy misalignment of peak scan matching method of Overhauser magnetometer, a fast tuning method based on multiple self-correlation algorithm is proposed in this paper. First, according to the characteristic that the Free Induction Decay(FID) signal has an exponential attenuation and constant frequency, the signal is subjected to multiple self-correlation de-noising processing, and the frequency of the FID signal is obtained by using the FFT. Then the simulation of MATLAB is carried out, and the result shows that the multiple self-correlation algorithm has better processing effect on the FID signal detection in the strong noise background, so the FID signal frequency is accurately obtained. Finally, tuning circuit structure and tuning work-flow is designed. The tuning capacitance value is obtained according to the FID signal frequency and the resonance formula. The capacitance is selected by multi-channel switch to realize fast tuning.