Front-end architecture for a multi-frequency electrical impedance tomography system

This paper provides a critical review of a number of the primary aspects of EIT system hardware presented in the literature. A thorough analysis of injection and measurement errors is presented to provide clarifying extensions to that provided by previous authors. From this basis, it proposes a novel design for a distributed parallel multi-frequency EIT system. The system described is modular, employs active electrodes to maximise CMRR (common mode rejection ratio) and was designed to employ digitally generated current injection and digital demodulation of the acquired signals.