A Seismic Signals Acquisition System Based On A Novel MEMS Sensor

Seismic signals are important for geological prospecting and people to understand earth’sstructure. But it is difficult to acquire accurately because of its low frequency and weak energy. Thetraditional systems have some disadvantages like big size, narrow band, high consumption andnarrow reliable dynamic operation range and so on while the system base on MEMS can achivethese requirements.This article designed a seismic signals acquition system including that geophone based onMEMS, detection circuit for the MEMS signal, and data gover system based on ARM9.Firstly, this article designed a novel MEMS micro-accelerometer to improve the dynamicoperation range, linearity and mechanical noise. With the actuators drived by electrostatic force thisnovel sensor have more bigger initial capacitance . By the tool MAXWELL, the influence of thedimension for the fringe effect is simulated while by the FEM tool, sport mode, strength, Transversesensitivity and air damping are simulated and analyzed whose results show that the slotted holecould decrease 60% of the mechanical noise, the sensor could not be destroy by the accelerationless than 1000g and the transverse sensitivity is nearly 0.Secondly, this article designed a detection circuit for the micro-accelerometer, composed of animproved carrier signal, inproved phase sensitive demodulation circuit, a band-pass filter and alow-pass filter. The simulated results show that the signal acquired is same as the initial accelerationsignal by the tool MULTISIM.Eventually the embed system based on ARM for data organization is designed and the code hasbe verified.