长周期大地电磁测深仪中电场信号采集电路研究

摘要

在长周期大地电磁测深仪中，探测的大地电场信号频率低、频带宽、能量弱、幅度小且易受环境噪声的影响。为了提高大地电场信号的测量精度，基于 STM32微处理器，以 TI 公司的运算放大器和模数转换器相结合，搭建了由增益放大器、低通滤波器、差分驱动器、高精度Δ-∑A/D转换器和微处理器组成的一种长周期大地电场信号数据采集电路。测试表明，采集电路的主要技术指标满足电场信号采集要求。%The earth electric field signal detected in the long period magneto-telluric Method is a low frequency,broad-band,weak energy,small amplitude signal and easily affected by environmental noise.According to these characteristics of the earth electric field signal,a long period the earth electric field data acquisition circuit,which mainly consists of a gain amplifier, low pass filter,differential driver and high-precisionΔ-∑A/D converter and microprocessor,was built in order to improve the measurement precision based on the STM32 microprocessor.It makes use of the TI's the operational amplifier and the ana-log-to-digital converter combined.The tests show that the main technical indexes of acquisition circuit can meet the acquisi-tion requirements of the earth electric field signal.