Broadband magnetic sensor

Abstract

The invention discloses a broadband magnetic sensor, belongs to an inductive magnetic sensor and solves the problem that the conventional magnetic sensor has extremely high noise in an extremely low frequency band. The broadband magnetic sensor comprises an induction coil, a high-frequency channel amplification circuit, a low-frequency channel amplification circuit, a low-pass filter, an operational amplifier, a voltage follower and a feedback circuit, wherein an output signal of the induction coil is respectively transmitted to the high-frequency channel amplification circuit and the low-frequency channel amplification circuit; the output end of the high-frequency channel amplification circuit is connected with a first switch; the output end of the low-frequency channel amplification circuit is connected with a second switch through the low-pass filter; central contacts of the first switch and the second switch are respectively connected with an inverse phase input end of the low-pass filter through a first input resistor and a second input resistor; and the output end of the operational amplifier is connected with the voltage follower and is connected with an induction signal input end of the induction coil through the feedback circuit. According to the broadband magnetic sensor, the low noise is amplified in the extremely low frequency band, the broadband magnetic sensor has flat amplitude-frequency characteristics and linear phase in wider frequency domains on two sides of the resonant frequency of the induction coil, and the application frequency range of the magnetic sensor is greatly widened.

Description

technical field [0001] The invention belongs to an inductive magnetic sensor, in particular to a broadband magnetic sensor used for magnetotelluric detection. Background technique [0002] In the field of magnetotelluric detection technology, it is necessary to collect magnetic field signals with a frequency of 0.00025Hz-10kHz. In order to realize this function, an inductive magnetic sensor is needed, and the main coil voltage of the inductive magnetic sensor is proportional to the frequency of the magnetic field signal. , the induced voltage is very small in the extremely low frequency band. Shao Yingqiu, Wang Yanzhang et al. proposed For broadband magnetic sensors amplified by direct amplification circuits, due to the large noise of the general direct amplification circuit in the extremely low frequency band, the signal-to-noise ratio of the output signal after amplification in the ultra-low frequency band is small, which is difficult to meet the detection requirements; th...

AI Technical Summary

Problems solved by technology

[0003] The invention provides a broadband magnetic sensor, which solves the problem of excessive noise in the extremely low frequency band of the existing magnetic sensor, so as to achieve lower noise in the entire working frequency band and flat amplitude-frequency characteristics on both sides of the resonance frequency of the induction main coil and linear phase

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