Researching On Digital Geophone Based On MEMS

This paper is based on the research of the sensor of MEMS technology, attached to the roadbed cave monitoring project, design a model MEMS digital geophone with higher accuracy to replace of the traditional analog geophone, breaking the monopoly of foreign technology. This paper surveys the state of development of geophone technology at home and abroad in some detail; making a brief analysis of the index requirements of the digital and miniaturized detector technology; we have done a comparative analysis between advantages and disadvantages of the imperative development of MEMS digital geophone and the traditional detector and digital geophones; at the same time, make the following research for MEMS digital geophone system suitable for the bridge engineering :① through the analysis of the working principle and research of structure of MEMS sensor, establishes the corresponding mechanical and electrical model, t made a post conditioning circuit design and implementation for the MEMS sensor of the project② MEMS sensor to collect the signal into an analog signal, the direct transmission will inevitably mixed with noise interference. In order to enhance the signal anti-interference ability, the fast digital transmission is necessary, this paper designed a high-precision 24 bit delta-sigma AD converter schematic and PCB diagram, And the AD sampling the baud rate can be selected by software control③ in order to further detect the exploration technology, the project design of 512 bit double buffer SDRAM chip, using FPGA micro control the processor caching and transmission speed④ after the completion of the whole hardware system, using signal Tap II to design system performance and accuracy which is verified by simulation.⑤ based on the dot NET platform, established the corresponding communication between MEMS digital geophone software, then design and implement a single detector data storage, display the real-time waveform and the function of format conversion;⑥ in the design of stable MEMS digital geophone system, in order to verify the effect of the detector performance data acquisition in complex environment, do a field test in the wild, study and analysis the time-frequency characteristics, noise interference on the collection data, the results show that the design of the detector is capable of seismic exploration requirements.In this paper, Under the premise of ensure the measurement accuracy, In this paper,the design of the detector mainly make breakthroughs in miniaturization and digital transmission, the results of the study will play a role on promote domestic development of digital geophone.