Research On Data Acquisition Module Of Broadband Seismic Recorder Based On ARM

Geodynamics disquisition of Tibetan plateau is the one of the most popular topics, developed countries ploughed into many funds in seismic exploration, it is advantaged using broad band seismic recorder in native seismic exploration and floor analyse seismic exploration, and it can offer constitution image with great depth, which provides approach to solve geodynamical problems. This thesis realized recording broad band seismic data based on ARM microcontroller , 24 bits high speed A/D and reading GPS information.This thesis have seven chapters, the structure and content include:The first chapter expounds the origin, background ,aim and meaning of investigation work , introduces the development of embedded system, introduces the work in the thesis.The second chapter brings forward two missions that are A/D data collection and receiving GPS information , aims at the mission , we accomplish system collection using ARM controller (AT91RM9200) as control kernel, CS5371+CS5372+CS5376 A/D conversion series chirp and FPGA (EPF10K20TC144) as A/D conversion circuit and Jupiter GPS receiver , and explain the reasons that using ARM controller and Linux operating system.The third chapter introduces character of ARM microcontroller and ARM series . defines the character of ARM controller (AT91RM9200), designs ARM controller hardware circuit, expounds the character of SDRAM,FLASH RAM and the circuit of SDRAM , FLASH RAM and ARM controller (AT91RM9200) , excuse the communication about system and computer by RS232 .The fourth chapter designs analog signal circuit, which turns the tiny seismic signal from seismograph to needed signal of 24 bits A/D conversion, the third recorder's forward amplifier is built up by two level basis circuit,which is coupled directly. The first level blows up input seismic signal, which uses low noise amplifier with program controlled, with a gain of×1,×2,×4,×8, PGA205 exports single signal , the second level is difference linear amplifier, switch the signal's output mode , offers double difference signal to 24 bits A/D conversion, which clears up input circuit's common-mode signal. 3 channel 24bits A/D conversion is made up by one CS5371 , one CS5372, one CS5376 and one EPF10K20TC144, GPS information is transmitted by RS485 standard, using MAX3485, introduces Jupiter GPS receiver, designs power circuit of this system : analog +5V, analog-5V, digital 5V,3.3V,1.8V. Analog +5V provides power to program control amplifier, analog switch and A/D conversion chip in collection board, digital 5V provides power to FPGA chip(EPF10K20TC144), GPS receiver, 3.3V source provides power to AT91RM9200 and its peripheral 3.3V chips , kernel power in AT91RM9200 is 1.8V.The fifth chapter introduces design of system software, introduces process of U-Boot and Linux kernel replanting . Serial communications setting of Linux includes setting baud rate , parity bit and stop bit, the most important is Serial communications setting in design serial communication program.The sixth chapter introduces experiment results of system , and analyses the results , which prove system functional validity .The seventh chapter sums up main investigation work , and brings forward next works .