【摘要】 目的 :针对生物电阻抗成像系统电流源需具备阻抗高、相移小等特点的要求,设计并实现一种高精度激励信号源。方法:基于二代电流传输器原理设计电压控制电流源,增加前级缓冲和直流反馈环节,负载端电路采用镜像反馈电路。结果:实现了激励信号的非接地安全释放,与改良Howland电流源相比,该电流源在1 MHz时输出阻抗可达250 kΩ以上,并具有更好的频率响应。结论:所设计的电流源可以更好地满足生物医学电阻抗成像系统信号源的要求。更多还原

【Abstract】 Objective To design and develop a high-precision exciting signal source to meet the requirements of biological electrical impedance tomography system for high impedance, low phase shift and etc. Methods A voltage controlled current source was designed based on the principle of the second-generation current conveyor, with the involvement of pre-buffering and DC feedback. A mirror feedback circuit was put at the load terminal. Results The drive signal was released safely without ground connection. Compared with modified Howland current source, the current source had the output impedance higher than 250 kΩ at 1 MHz, which also had high frequency response. Conclusion This current source meets the requirements of drive signal source for the biological electrical impedance tomography system.更多还原