瞬变电磁低噪声前置放大器研制  

Research on low noise preamplifier of transient electromagnetic instrument

作　　者：胡子君[1] 宋刚 陈兴朋[1] 席振铢[1] 黄龙 周胜 

机构地区：[1]中南大学地球科学与信息物理学院,长沙410083 [2]长沙五维地科勘察技术有限责任公司,长沙410205

出　　处：《地球物理学进展》2012年第6期2704-2709,共6页Progress in Geophysics

基　　金：危机矿山接替资源大比例尺定位预测基础研究(2007CB416608)资助

摘　　要：为了增大瞬变电磁勘探深度,充分利用晚期道数据,针对瞬变信号频带宽等特点和低噪声运放放大电路的设计原则,通过对放大电路的噪声来源和降低噪声措施的研究,设计了基于超低噪声运算放大芯片LT1028的低噪声差分前置放大电路.建立模型对噪声进行计算和仿真,得出的单运放噪声和总噪声分别为3.2uVrms和4.53uVrms.对实际电路进行噪声测试,得到的噪声频谱图表明在0～100kHz的频率范围内,电路噪声在10～20uVrms之间,设计的差分前置放大电路具有很低的噪声水平,能够满足瞬变信号前置放大的需要.ransient electromagnetic method is widely used in many fields such as mineral exploration,groundwater exploration and engineering survey.In order to increase the transient electromagnetic exploration depth,making full use of the advanced way data,we design a low noise and differential preamplifier circuit,and also analyze its noise,based on the principles of low noise amplifier circuit designing,and the characteristics of TEM signal of wide frequency band,dynamic range,and huge differences between late and early signals in amplitude and decay rate.Two low noise amplifiers LT1028 are used in this design to reduce the circuit noise.The simulation results and the theoretical calculation results of the noise are completely consistent.And the circuit noise spectrum chart we get by measuring indicates that the circuit we designed has a low noise level,which can satisfy the needs of transient signal preamplifier.

关 键 词：瞬变电磁 前置放大 差分信号 低噪声 

分 类 号：P631[天文地球—地质矿产勘探]