Design Of High Dynamic Range Self-storage Low Frequency Microseismic Signal Acquisition System

Microseismic signal monitoring technology has a wide range of applications in mining,bridge construction,geological survey,oil and gas survey,hydraulic fracturing,etc.Microseismic signal acquisition is an important part of microseismic signal monitoring,and its signal acquisition quality,dynamic range,and acquisition accuracy have an important impact on the location and analysis of microseismic events.At present,the geophones used for microseismic signal monitoring mainly rely on imports and are expensive,bulky,and complicated to install.Meanwhile,due to the limitations of materials and processing technology,the natural frequency of the geophone can not be effectively reduced by changing the structure of the geophone itself.Therefore,it is of great practical significance to design a low-frequency microseismic signal acquisition system with high dynamic range and high sampling accuracy.Starting from the basic requirements of the microseismic signal acquisition system,this thesis realizes the low-frequency microseismic signal acquisition and storage system through the digital low-frequency compensation algorithm design on the STM32 series microcontroller,which is combined with the analog-to-digital conversion module with the feature of high dynamic range and high sampling accuracy.This paper mainly completes the following work:Firstly,we select a velocity vibration sensor with lower output impedance and higher signal-to-noise ratio as the pickup device for microseismic signals.This sensor can measure vibration signals with small amplitude and has the lower natural frequency providing the basis for the digital low-frequency compensation algorithm.For the front-end signal acquisition unit,a high-fidelity front-end signal conditioning circuit with functions of amplification,filtering and programmable gain is designed to effectively improve the anti-interference ability.At the same time,the automatic gain adjustment capability is realized.Thereafter,the ADS1282-based analog-to-digital conversion process is controlled by STM32F103ZET6 to realize the high-speed and high-precision A/D conversion of the microseismic signal,and the SDIO mode combined with the FATFS file system is used to fastly storage the analog-to-digital conversion data.In order to effectively improve the performance of acquiring low-frequency components of microseismic signal,a digital low-frequency compensation algorithm is designed based on the principle of zero-pole compensation.After the corresponding algorithm simulation,the digital low-frequency compensation algorithm is designed and implemented based on the STM32 platform.The low-frequency compensation software broadens the frequency response range of the microseismic signal acquisition system and realizes the effective acquisition of the low-frequency components of the microseismic signal.Finally,the function of the designed microseismic signal acquisition system is verified through testing.