Research on CSAMT Emission Current Recording System Based on FPGA

In controlled source audio-frequency magnetotellurics (CSAMT), we often obtain data through recording transmitted signals by receivers. But in the actual exploration, electromagnetic interference is serious and useful, signals are always contaminated by noise and interference signals. This paper focuses on recording and storing the original emission signal for subsequent data processing simultaneously, combined with the signal characteristics of wide band and large dynamic range, and proposing a data acquisition system with high anti-interference and high resolution is needed. The system consists of filter and amplifier module, A/ D conversion module, storage module, digital signal processing and logic control module and GPS synchronous sampling module, with the current acquisition range from O.lA to 50A, the frequency range from O.lHz to 10kHz, and the current recording accuracy above 90%. After the test, CSAMT emission current record system based on the GPS Synchronous meets the design requirements.