Research on measuring technology and data processing method of multi-frequency bio-impedance

The bioelectrical impedance technology is a non-invasive detecting technique which extracts biomedical information according to the electricity characteristic or the change of biology tissue and apparatus. In this paper, we introduce the multi-frequency technique to measure bio-impedance and data processing method. The technique mainly includes multi-frequency impedance spectroscopy measurement and methodology to evaluate impedance in mixing frequency excitation mode. The multi-frequency impedance spectrum measurement focuses on applying three-element model and Cole-Cole model to extraction of impendence spectrum information in three different frequency-selective modes. In methodology to evaluate impedance in mixing frequency excitation mode, we mainly introduce a signal processing method based on multi-sampling frequencies, a single sampling frequency and sparse sampling frequencies. A signal demodulation method employing discrete Fourier transform and virtual reference point is also investigated.