Application Of SoPC Technology In Engineering Seismograph

Shallow seismic method has been developing rapidly as a result of theengineering construction need since1980s. The number of channels that refractionwave method and reflection wave method commonly used are24,48or96. However,the number of channels that pile testing usually required is1,for micromovementmeasuring is3and for surface wave is6to12. According to this need, we proposeda SoPC system named DZG96engineering seismograph by using Cyclone III FPGAof Altera.It can realize large dynamic range, high precision data acquisition, digitaldisplay and storage for the shallow seismic exploration. It not only can realizerefraction wave method and reflection wave method, but also could realize pile testand and micromovement measuring.DZG96engineering seismograph is composed by the centralized48-channelengineering seismograph and distributed48-channel. The centralized48-channelengineering seismograph comprises a bottom board, power board, analog board,main control board, PC104. The distribute48-channel consists of four DZG12whichhas12-channel. Each DZG12have a power board, analog board, control board. Inthis thesis, we mainly discuss the centralized48-channel’s analog board, controlboard and DZG12.Analog board have12channels. So the centralized48-channel have four analogboard,each composed of a power unit, control unit, A/D unit, D/A unit, analog signalamplification unit, channel selection unit. Data transmission between analog boardand control board use Manchester coding and the data transfer rate is34.816Mbps.Manchester encoding is a self-written program, parallel/serial conversion and codeall implemented in FPGA.The system use Control board as the communication hinge between PC104andanalog board, it would handle command received from the PC104, then send it toanalog board, it also collect data from analog board. Its receiver’s oversampling clock is278.571MHz. Manchester decoder can identify the data header, then encodethe fellowing serial data, and transfer serial data into parallel data which wouldstorage in SDRAM. The network would send these date to PC104. Control board’sdata transmission refers to RS232, Ethernet network and LVDS.DZG12’s control board control its analog board collecting data, sending its dataand repeating next station’s data, receiving and forwarding the centralized48-channel’s command. Its power board is responsible for supplying power for itsanalog board and control board. Data transmission uses two independent Ethernet.The two DM9000A could automatic addressing.