System and method for increasing signal-to-noise ratio of Larmor precession signal of Overhauser magnetic sensor

Abstract

The invention provides a system and method for increasing the signal-to-noise ratio of a Larmor precession signal of an Overhauser magnetic sensor. The system comprises the Overhauser magnetic sensor,a sensor excitation unit, an FID signal processing unit and a power supply battery, wherein a signal excitation end of the Overhauser magnetic sensor is connected with a radio frequency excitation signal in the sensor excitation unit, a signal receiving end of the Overhauser magnetic sensor is connected to a direct-current pulse excitation end and the FID signal processing unit through a single-pole double-throw switch, and a signal connection path of the Overhauser magnetic sensor is selected by controlling the single-pole double-throw switch. According to the method, an LC resonance and narrow-band filter is utilized firstly to limit the frequency band of the Larmor signal, primary noise reduction is performed, a time-frequency peak filtering algorithm is used for performing secondary noise reduction and signal reconstruction on the Larmor signal, random noise and noise introduced by a conditioning circuit can be further suppressed, and the signal-to-noise ratio of the Larmor signalis substantially increased.

Description

technical field [0001] The invention relates to the technical field of electronic information, in particular to a system and method for improving the signal-to-noise ratio of an Overhauser magnetic sensor Larmor precession signal. Background technique [0002] Overhauser magnetic sensor is a high-precision magnetic field measurement sensor based on the principle of nuclear magnetic resonance and electron paramagnetic resonance. It can be used in geomagnetic field observation, geological resource exploration, underground unexploded bomb detection and other fields. Its working principle is to use high-frequency excitation and short-term DC excitation to act on the free radical solution inside the sensor. After the DC excitation is removed, the protons in the free radical solution will perform precession around the direction of the geomagnetic field, and pass through a set of reversely connected induction coils. Receive the Larmor precession signal, the frequency of the precess...

AI Technical Summary

Problems solved by technology

[0003] At present, the method of improving the signal-to-noise ratio of the Larmor precession signal of the Overhauser magnetic sensor mainly focuses on the circuit hardware. The signal-to-noise ratio of the Larmor signal is improved through LC resonance, narrow-band filtering and other filter circuits, although it can effectively shorten the frequency band and improve Signal-to-noise ratio, but there are still the following problems: 1) There is no good suppression for random noise; 2) The hardware circuit will introduce circuit noise, adding new noise sources, and it is difficult to obtain a higher signal-to-noise ratio Larmor precession Signal

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