Ross Alexander S, Saulnier G J, Newell J C, Isaacson D
Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA.
Physiol Meas. 2003 May;24(2):509-16. doi: 10.1088/0967-3334/24/2/361.
Questions regarding the feasibility of using electrical impedance tomography (EIT) to detect breast cancer may be answered by building a sufficiently precise multiple frequency EIT instrument. Current sources are desirable for this application, yet no current source designs have been reported that have the required precision at the multiple frequencies needed. We have designed an EIT current source using an enhanced Howland topology in parallel with a generalized impedance converter (GIC). This combination allows for nearly independent adjustment of output resistance and output capacitance, resulting in simulated output impedances in excess of 2 Gohms between 100 Hz and 1 MHz. In this paper, the theoretical operation of this current source is explained, and experimental results demonstrate the feasibility of creating a high precision, multiple frequency, capacitance compensated current source for EIT applications.
关于使用电阻抗断层成像（EIT）检测乳腺癌的可行性问题，或许可以通过构建一台足够精确的多频EIT仪器来解答。对于此应用而言，电流源是理想之选，但尚未有报道称存在能在所需的多个频率下具备所需精度的电流源设计。我们设计了一种EIT电流源，它采用增强型霍兰德拓扑结构与广义阻抗变换器（GIC）并联。这种组合允许对输出电阻和输出电容进行近乎独立的调节，从而在100赫兹至1兆赫兹之间产生超过2吉欧的模拟输出阻抗。本文阐述了该电流源的理论运行情况，实验结果证明了为EIT应用创建一个高精度、多频、电容补偿电流源的可行性。
