Method for improving frequency measuring precision of larmor signal of Overhauser magnetometer and circuit thereof

A signal and precision technology, used in the field of improving the frequency measurement accuracy of the Larmor signal of the Overhauser magnetometer, can solve the problem of difficult and high-precision frequency measurement, and achieve the goal of improving the overall measurement rate, reducing the cost of transformation, and increasing the effective frequency measurement time. Effect

Inactive Publication Date: 2015-07-29
CHINA UNIV OF GEOSCIENCES (WUHAN)
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Problems solved by technology

Therefore, this hardware-based frequency measurement scheme is difficult to achieve high-precision frequency measurement due to its inherent defects.

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  • Method for improving frequency measuring precision of larmor signal of Overhauser magnetometer and circuit thereof
  • Method for improving frequency measuring precision of larmor signal of Overhauser magnetometer and circuit thereof
  • Method for improving frequency measuring precision of larmor signal of Overhauser magnetometer and circuit thereof

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Embodiment Construction

[0032] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] Such as figure 1 As shown, the present invention improves the circuit of Overhauser magnetometer Larmor signal frequency measurement accuracy, including Overhauser sensor, working material excitation circuit, conditioning circuit, ADC converter, FPGA, data memory SDRAM, embedded controller ARM 11, LCD display , a keyboard, a USB interface and an SD card, the input end of the Overhauser sensor is connected to the working material excitation circuit, the output end is connected to the input end of the conditioning circuit, the output end of the conditioning circuit is connected to the FPGA through the ADC converter, and the FPGA is respectively connected to the data The memory SDRAM, the embedded controller ARM 11 and the working substance exc...

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Abstract

The invention discloses a method for improving frequency measuring precision of a larmor signal of an Overhauser magnetometer and a circuit thereof. The circuit comprises an Overhauser sensor, a working substance exciting circuit, a conditioning circuit, an ADC (Analog Digital Converter), an FPGA (Field Programmable Gate Array), a data memory SDRAM (Synchronous Dynamic Random Access Memory) and an embedded controller. The measurement of the frequency of the larmor signal is converted into a frequency domain from a conventional time domain; frequency measurement is realized by using a method combined by an FFT (Fast Fourier Transform) algorithm and a CZT (Chirp Z Transform) algorithm: a rough frequency value of a current signal is obtained by using the FFT algorithm, and local narrowband spectrum zooming is performed by using the CZT algorithm in a narrowband range with the rough value as a central point so as to realize high-precision frequency measurement; the inherent defect of shaping error which occurs when a signal index is attenuated to the later stage in the existing hardware frequency measurement scheme is overcome, new error is not introduced, the frequency measuring precision of the magnetometer is improved to 0.001Hz, and the integral measuring speed of the instrument is improved while the frequency measuring effective time is increased; the upgrading of the frequency measuring scheme in the later stage is convenient, and the reconstruction cost of the instrument is effectively reduced.

Description

technical field [0001] The invention relates to the technical field of magnetometer measurement, in particular to a method and a circuit for improving the frequency measurement accuracy of an Overhauser magnetometer Larmor signal. Background technique [0002] The Overhauser magnetometer is a weak magnetic measurement technology based on the ordinary proton precession magnetometer, which uses the dynamic nuclear polarization effect of free radicals. The Larmor signal obtained by it is one higher than that of the ordinary proton precession magnetometer. Magnitude. Compared with other magnetic field measurement technologies, the magnetometer has the characteristics of high sensitivity, low power consumption, no heading error, and no dead zone, so it has been widely used in resource exploration, aerospace, military and other fields. Since the Overhauser magnetometer measures the frequency of the Larmor signal output by the sensor, and then uses the magnetic rotation ratio cons...

Claims

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Application Information

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IPC IPC(8): G01V3/40G01V3/38
Inventor 葛健董浩斌彭义刘欢
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)
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