三维电场传感器微弱信号放大电路的设计与实验研究

Design and Experimental Study of Weak Signal Amplification Circuit for Three-dimensional Electric Field Sensor

针对场磨式三维电场传感器产生的信号微弱、信噪比不足,且存在零点漂移等现象,导致无法进行有效的A/D转换的问题,研究了一种包含I-V积分变换电路、差分放大电路以及偏置电路的放大电路,对传感器产生的微弱信号进行放大、平移处理达到A/D转换要求。通过Multisim 12.0仿真对I-V积分变换电路中的反馈电阻与积分电容的参数进行优化,优化了电路的通频带的中心频率和带宽;设计了一种二级差分放大电路及偏置电路,满足了信号的A/D转换要求。将场磨式三维电场传感器的输出信号经过设计的放大电路进行实际测试,实验证明了本电路有效提高了信号放大电路的灵敏度,提高了信号的信噪比,同时提高了电路的抗干扰能力。

Aiming at the problem that the field mill type three-dimensional electric field sensor can not carry out effective A/D conversion,which was caused by weak signal,insufficient signal-to-noise ratio and zero drift,a kind of amplifier circuit including I-V integral conversion circuit,differential amplifier circuit and bias circuit was studied.The weak signal generated by the sensor was amplified and translated to meet the A/D conversion requirements.The parameters of feedback resistance and integral capacitance in I-V integral conversion circuit were optimized by Multisim 12.0 The center frequency and bandwidth of the pass band were optimized.A two-stage differential amplifier circuit and bias circuit were designed to meet the requirements of A/D conversion.The output signal of the three-dimensional electric field sensor is tested by the designed amplifier circuit,the sensitivity,SNR and anti-interference ability of signal amplifier circuit are improved effectively.