The Research On Key Problems Of Signal Processing And Embedded Software And Hardware Design

With the continuous development of society and economy,the rational utilization and exploitation of underground natural resources have become the universal research object of society,and the use of micro-motion technology for geological investigation has become the mainstream direction.Traditional wireline exploration system is expensive and difficult to construct.To reduce costs and increase efficiency,cable-less exploration systems were created,However,there is still a lack of a cable-free system especially suitable for the detection of fretting.The existing cable-free seismographs are not ideal for the detection of fretting because of their large volume and low accuracy.To solve this problem,this paper designs an integrated portable micro-motion acquisition instrument suitable for micromotion detection,which has the characteristics of low cost,integration,and high precision.The micro-motion instrument designed in this paper takes STM32 microcontroller as the core,uses an orthogonal three-component moving-coil speed detector to collect vibration signals,and at the same time uses a 32-bit high-precision A/D conversion module AD7177,equipped with large capacity storage space,wireless and Ethernet transmission,GPS positioning,in order to meet the micro-motion field detection data acquisition,monitoring,storage and recovery.And the following studies are made on the key issues of signal processing.First,the key issues of low-frequency signals are dealt with,and a low-frequency compensation circuit is designed.the lower limit of the low frequency of the moving-coil detector is increased from 4Hz to 0.2Hz through the compensation circuit so that the ability of the instrument to acquire low-frequency signals is improved.Secondly,the noise,power consumption,and precision of the instrument are studied.Through the circuit and component selection design,a micro-motion acquisition instrument with low noise,low power consumption,and high precision is realized.The whole instrument is composed of two parts: hardware and software.The hardware part is divided into analog circuit,digital circuit,and power supply circuit.The analog circuit is composed of the pre-signal amplifying circuit,filter circuit,program-controlled amplifying circuit,and analog-to-digital conversion circuit.Digital circuit includes a microcontroller minimum system and various peripheral modules and interfaces;The power supply circuit includes all levels of voltage conversion circuit.The software is divided into upper computer and lower computer design,the upper computer is responsible for parameter setting and instruction of the instrument,as well as the later data recovery;The lower computer is responsible for completing the instructions of the upper computer,including synchronous acquisition and analog-to-digital conversion.Finally,after the design of the instrument was completed,the whole system was tested.Through the indoor performance test,it was determined that the instrument could meet the needs of micro-motion detection.After that,a small-scale field test was carried out on the top of the urban tunnel(in Shenzhen Dayun Park),which further verified the effectiveness of the instrument and proved that the overall design of the instrument is reasonable and suitable for geological investigation.