Electromagnetic pulse noise restraining method and device for detecting magnetoacoustic signals

Abstract

The invention discloses an electromagnetic pulse noise restraining method and device for detecting magnetoacoustic signals. The method comprises the following steps: the amplitudes and the pulse widths of synchronization pulses needed by a variable gain amplifier are calculated; synchronous pulse signals are set; the variable gain amplifier restrains electromagnetic pulse noise, and amplifies useful signals. The device comprises a power supply, a synchronous pulse generation device and the variable gain amplifier, wherein the power supply input end of the variable gain amplifier is connected with the power supply through a second isolating circuit; the reference voltage input end of the variable gain amplifier is connected with the power supply sequentially through a first voltage stabilizing circuit and a first isolating circuit; the gain control signal input end of the variable gain amplifier is connected with the synchronous pulse generation device for outputting control signals to the variable gain amplifier; the magnetoacoustic signal input end of the variable gain amplifier is connected with an ultrasonic transducer for outputting magnetoacoustic signals to the variable gain amplifier. The method and the device can effectively restrain the pulse electromagnetic noise doped in the weak signal detecting process, and can simultaneously realize the function of amplifying the detected signals.

Description

technical field [0001] The invention relates to a method for suppressing electromagnetic pulse noise. In particular, it relates to an electromagnetic pulse noise suppression method for magnetoacoustic signal detection and a device thereof, which utilizes the gain control capability of a variable gain amplifier to suppress noise. Background technique [0002] The variable gain amplifier (VGA) is a key component of the automatic gain control system (AGC), its main function is to change the system gain, adjust the dynamic range and perform power control. Its main features are high dynamic range and high linearity, in addition to having a high signal-to-noise ratio. [0003] Impulsive noise is discontinuous, consisting of irregular pulses or noise spikes with short duration and large amplitude; duration ≤ 0.5s, interval > 1s, sound pressure RMS change ≥ 40dB (A). Impulse noise can be generated for a variety of reasons, including electromagnetic interference, failures and de...

AI Technical Summary

Problems solved by technology

The electromagnetic pulse propagates through the space and is detected by the transducer, which generates a large-value output signal at the output part of the transducer, which seriously affects the performance of the detection system

Due to the large-value characteristics of impulse noise, on the one hand, it is easy to submerge the detected signal, and on the other hand, it is not conducive to the post-processing of weak signals, such as: limiting the amplification factor of the signal, affecting the analog-to-digital conversion, etc.

At the same time, the unique frequency characteristics of this section of electromagnetic pulse noise (in the same frequency band as the detected signal) limits its processing by frequency and other methods

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