Jossinet J, Tourtel C, Jarry R
Institut National de la Santé et de la Recherche Médicale INSERM U281, Lyon, France.
Physiol Meas. 1994 May;15 Suppl 2a:A83-90. doi: 10.1088/0967-3334/15/2a/012.
The characterization of tissue by means of electrical impedance tomography requires accurate impedance measurements at relatively high frequencies. The present study describes the design and fabrication of broad-band, active, current electrodes for in vivo measurements. This approach eliminates the lead capacitances of the sourcing electrodes. The value of the resistors used were computed according to a protocol taking into account the constraints of a given application and the values and tolerances of the available components. Additional selection of the components further reduced the variability in circuit performance. The current sources designed according to the method described are usable at frequencies higher than 1 MHz, for differential load impedances up to 2000 omega. The parallel output conductance for each active electrode is 0.85 microS +/- 2%. The design method is valid for either adjacent or diametric drive, and can be applied to various applications by modifying the shape of the electrode.
通过电阻抗断层成像对组织进行表征需要在相对较高频率下进行精确的阻抗测量。本研究描述了用于体内测量的宽带、有源电流电极的设计与制作。这种方法消除了源电极的引线电容。所使用电阻器的值是根据一个协议计算得出的，该协议考虑了给定应用的限制以及可用组件的值和容差。对组件的进一步选择进一步降低了电路性能的变异性。根据所述方法设计的电流源在高于1 MHz的频率下、对于高达2000欧姆的差分负载阻抗是可用的。每个有源电极的并联输出电导为0.85微西门子±2%。该设计方法对于相邻驱动或直径驱动均有效，并且通过修改电极形状可应用于各种应用。
