Magnetic resonance three-component noise removing device and noise removing method

Abstract

The invention relates to a magnetic resonance three-component noise removing device. The magnetic resonance three-component noise removing device is formed through a structure. The structure is characterized in that an upper computer is connected with a transmitting coil through a control system, a transmitting circuit and a resonance matching capacitor; the transmitting circuit is connected with a power supply; the control system is connected with a receiving coil and a reference coil respectively through an A / D (Analog to Digital) collection and amplification circuit and a conditioning circuit. The magnetic resonance three-component noise removing device is applicable to a detection area with complex and changeable environment noise and uneven space distribution of the noise; due to the adoption of relevance between x-component signals, y-component signals and z-component signals which are sensed by coils paved in the same detection place, the z-component noise is removed, then filtered and processed to obtain reliable magnetic resonance signals, so that the wiring space is greatly saved and the processing result is flexible and accurate; in particular, when sharp-peak noise with great amplitude exists, the noise removing effect is excellent. Through the magnetic resonance three-component noise removing device, the influence of strong electromagnetic interference near the cities, the villages and the water-deficient areas is eliminated, and the problem of limited application of a nuclear magnetic resonance underground water detection method is solved.

Description

Technical field: [0001] The invention relates to a geophysical detection method and its data interpretation, in particular to a data processing method for acquiring a three-component nuclear magnetic resonance (NMR) groundwater detection method and using the three-component magnetic resonance to eliminate noise. Background technique: [0002] As a method of detecting groundwater directly, NMR groundwater detection method has the advantages of high resolution, high efficiency, rich information and uniqueness. However, because the signal received by the instrument is very weak (nanovolt level), the high-sensitivity receiving device is very susceptible to interference from the noise components of the surrounding environment. China has a dense population and a well-developed power grid. Power lines and electrical equipment are full of towns and villages. Electromagnetic interference is serious. Most of the water-deficient areas are located in areas with strong interference such as ci...

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Problems solved by technology

[0005] The power frequency harmonic interference suppression circuit of the above invention can only solve the filtering of a certain power frequency harmonic in the useful signal frequency band, but is helpless for electromagnetic interference such as other power frequency harmonics and singular noise; the groundwater detection method with a reference coil It is required that the noise signal in the reference coil and the magnetic resonance signal have a good correlation, so the distance between the reference coil and the main coil is at least greater than twice the wire diameter, which increases the wiring space, and due to the complexity, variability and Inhomogeneity of spatial distribution, sometimes the ideal denoising effect cannot be obtained

[0006] Aiming at the problem of noise interference in magnetic resonance signals, methods such as laying special-shaped coils and increasing the number of signal superpositions, block cancellation, sine cancellation and notch filters are also used to filter out electromagnetic noise. , these methods achieve better results under certain preconditions, but when the noise intensity is large, the interference components are complex, and the frequency difference between the signal center frequency and the power frequency interference is small, it is difficult to obtain a better filtering effect

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