Design Of Digital Seismometer

Digital seismometer is the core equipment of geophysical exploration, in which seismic wave is converted to digital signal that provides the basis for analysis the petro storage conditions. With the development of electronic information technology, digital seismometers gradually replaced the traditional analog seismometer. Compared with analog seismometers, digital seismometer has the character of high precision and low failure rate, light weight, small volume and networking, etc.The thesis discussed the core units:sigma-delta modular and digital decimation filter in detail, and designed the software of terminal synchronization and SD card storage. The main content is listed as following:1. To discuss the principle of∑-△modulator and designed the circuit. Researched the digital decimation filter deeply, analysised several algorithms such as:CIC filter, ISOP filter and Half-band filter, and then given the effectiveness of ISOP filter in compensation CIC filter.2. This parameters of filters were optimized and the ripple wave of CIC filter was analysed by Matlab. By design the ISOP filter and simulate the CIC_ISOP filter. Finally, two stages Half-band filter is designed by Fdatool of matlab.3. The scheme of terminal synchronization was researched, explained the principle of GPS time synchronization and gives the software flowchart.4. Analysed deeply the way of realization of FAT32 file system, and gived the software flowchart.5. Finally, testing result of key units was given in laboratory.