Temporal resolution of the impedance locus measurement using digitally constructed current waveform

摘要

The temporal-resolution of the frequency-domain method for the identification of the impedance locus depends on the basis frequency used in the current waveform construction, i.e. the higher basis frequency provides the better temporal resolution. The impedance locus can be characterized by the impedance parameters. The frequency distribution in impedance locus, accordingly the accuracy of the estimated impedance parameters with limited number of data, highly depends on the level of impedance. Therefore, this paper investigated the relationship between the estimation accuracy of the impedance parameters and the frequency coverage of the impedance locus in relatively low to high impedances (51kΩ～45MΩ). As the basis frequency, 100Hz was enough for the usual impedance less than 203kΩ. On the other hand, 10Hz and 1Hz was required for the medium-level (517KΩ) and high-level (45MΩ) impedance. The results of this study are expected to serve as the reference of the frequency selection in the frequency-domain analysis of the skin impedance.