摘要
航空Z轴倾子电磁测量系统（ZTEM）空心感应磁传感器的感应线圈具有源阻抗大的特点,并且调理电路需要设置高通滤波器来抑制低频干扰。为实现电路的低噪声设计,针对感应线圈源阻抗大的问题,第一级采用以差分结型场效应管（JFET）对管为核心器件的负反馈结构,通过对第一级电路进行噪声建模,得出只有当JFET电压噪声是唯一主要噪声源时,电路整体性能最优的结论;针对低频部分,由于高通滤波器影响导致电路噪声特性被抬高的问题,通过优化第一级电路增益和高通滤波器截止频率的方法得以改善。实验结果表明,该电路结构简单,调试方便,其电流噪声为11 fA/√Hz,电压噪声为4 nV/√Hz@30Hz和2 nV/√Hz@1kHz。与超低噪声放大器LT1028和OPA827的对比实验表明,自制电路在ZTEM空心感应线圈动态阻抗范围内,噪声性能优异,满足ZTEM信号调理电路低噪声优化设计的预期要求。
The ZTEM airborne aircoil induction coil has large source impedance and the conditioning circuit needs to set a high-pass filter to suppress low-frequency interference. The large source impedance of the induction coil is firstly focused in the design of low noise circuit. The first-stage circuit uses a negative feedback structure with a differential JFET tube as the core component. Through the noise modeling of the first-stage circuit, it is concluded that only when the JFET voltage noise is the main noise source, the overall circuit performance is optimal. For the low frequency part, circuit noise characteristics are elevated due to high-pass filter effects. By optimizing the first-stage gain and high-pass cutoff frequency, the performance of the first-stage circuit is improved. The experimental results show that the circuit has a simple structure and is easy to adjustment. The current noise of the circuit is 11 fA/√Hz, the voltage noise is 4 nV/√Hz@30 Hz and 2 nV/√Hz@1 kHz. Compared with the ultralow noise amplifier LT1028 and OPA827, the designed circuit has superior noise performance in the dynamic range of the induction coil and meets the expected requirements of low noise optimized design of ZTEM signal conditioning circuit.
作者
王言章
石佳晴
时洪宇
Wang Yanzhang;Shi Jiaqing;Shi Hongyu(Key Laboratory for Geophysical Instrumentation of Ministry of Education,Changchun 130026,China;College of Instrumentation ＆ Electrical Engineering,Jilin University,Changehun 130026,China)
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2018年第9期187-194,共8页
Chinese Journal of Scientific Instrument
基金
国家重点研发计划(2017YFC0601802)
国家自然科学基金(41274183)
吉林省科技创新人才培育计划(20160519023JH)
吉林省省校共建计划专项(SXGJQY2017-11)项目资助
关键词
调理电路
低噪声
高源阻抗
参数优化
conditioning circuit
low-noise
high source impedance
parameter optimization
作者简介
王言章（通信作者），分别在2002年、2005年和2010年于吉林大学获得学士学位、硕士学位和博士学位，现为吉林大学教授，主要研究方向为弱磁传感器、地球信息探测仪器。E—mail：yanzhang@jlu．edu．cn;石佳晴，2017年于吉林大学获得学士学位，现为吉林大学硕士研究生，主要研究方向为弱磁传感器。E—mail：shijq17@mails．jlu．edu．cn
