基于OPA140的直流激电仪低噪声模拟前端电路开发  

Development of low noise simulation front-end circuit of IP instrument based on OPA140

作　　者：罗星白 王鹤[1] 席振铢[1] 韦洪兰 薛文涛 Luo Xingbai;Wang He;Xi Zhenzhu;Wei Honglan;Xue Wentao(School of Geosciences and Info-physics,Central South University;Hunan Wuwei Geological Technology Co.,Ltd.)

机构地区：[1]中南大学地球科学与信息物理学院 [2]湖南五维地质科技有限公司

出　　处：《黄金》2022年第8期49-54,共6页Gold

基　　金：国际海域资源调查与开发“十三五”项目(DY135-S1-1-07)。

摘　　要：直流激电法是一种重要的金属矿找矿方法,但是激电信号微弱,且易受电磁信号干扰。基于OPA140功放芯片,设计了输入保护电路、前置放大电器、自然电位补偿电路、低通滤波器及ADC单端转双端电路,实现了对低噪声模拟前端电路的开发,提高了整个系统的信噪比。并采用动态信号分析仪和频谱分析仪测试了模拟前端电路噪声和频响特性,利用TINA-TI软件平台仿真计算了前置放大器的等效输入电压噪声,测试结果均符合实际需求。将设计好的模拟前端电路与控制板相结合做出样机,与ELREC 6直流激电仪进行对比试验,试验结果表明:样机与ELREC 6直流激电仪的视极化率整体走势一致,可为模数转换器提供高质量信号,低噪声模拟前端电路开发达到了设计要求。The IP method is an important metal prospecting method.However,the IP signal is weak and easily interrupted by electromagnetic signals.Therefore,based on the OPA140 power amplifier chip,the input protection circuit,pre-amplifier,self-potential supplement circuit,low-pass filter,and the circuit transiting from ADC single-ended to double-ended are designed,realizing the development of low noise simulation front-end circuit,improving the ratio of signal and noise.Besides,a dynamic signal analyzer and spectrum analyzer are used to test the response of simulation front-end circuit noise and frequency.TINA-TI software platform simulates and calculates the equivalent input voltage noise of the pre-amplifier,and the test results are consistent with actual needs.The designed simulation front-end circuit is combined with the control panel to make a prototype,which is compared with ELREC 6 direct IP instrument.The results show the parallactic polarizability of the prototype,on the whole,goes with ELREC 6 IP instrument.The prototype can provide a high-quality signal for ADC.The development of low noise simulation front-end circuit meets the design requirements.

关 键 词：直流激电仪 模拟前端电路 OPA140 等效输入电压噪声 低噪声 

分 类 号：TD178[矿业工程—矿山地质测量]