Bioimpedance measurement using mixed-signal embedded system

The Electrical Impedance Spectroscopy (EIS) has been recently proposed as a simple non-invasive technique to characterize biological materials, and observe signals and physiological parameters. While the technique capabilities are still questioned, a simple and low-cost system based on a mixed-signal circuit is capable of performing this kind of measurements for testing different materials, like tissues with minimal effort. The system includes a DDS sine waveform generator, a voltage controlled current source, a programmable mixed-signal circuit and an Analog Front-End (AFE) for signal acquisition. From the simulation and experimental results, it is possible to say the designed system is suitable for applications that require wide frequency and load ranges, being an excellent option for EIS and Electrical Impedance Tomography (EIT) applications.