Saulnier Gary J, Ross Alexander S, Liu Ning
Department of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA.
Physiol Meas. 2006 May;27(5):S221-36. doi: 10.1088/0967-3334/27/5/S19. Epub 2006 Apr 24.
Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes the capability of measuring both the applied voltage and applied current. A calibration circuit and calibration algorithm are described which enables all voltage sources in an EIT system to be calibrated to a common standard. The calibration minimizes the impact of stray shunt impedance, passive component variability and active component non-ideality. Simulation data obtained using PSpice are used to demonstrate the effectiveness of the circuits and calibration algorithm.
电阻抗断层成像（EIT）利用放置在身体表面的电极来确定体内的复电导率分布。EIT可以通过在电极上施加电流并测量电极电压来实现，或者通过施加电极电压并测量电流来实现。也已经开发出了使用电压源施加所需电流的技术。本文描述了一种用于施加电压EIT的电压源，该电压源具有测量施加电压和施加电流的能力。文中描述了一种校准电路和校准算法，可使EIT系统中的所有电压源校准到一个通用标准。该校准可将杂散并联阻抗、无源元件变化和有源元件非理想性的影响降至最低。使用PSpice获得的仿真数据用于证明电路和校准算法的有效性。
