Modular System for Spectral Analysis of Time-Variant Impedances

摘要

Electrical bioimpedance of living tissues changes over time due to heart beating and breathing. To measure the changes in impedance spectrum requires sophisticated instrumentation. In this paper, a modular system for fast measurement of the time-variant spectrum of the time dependent (dynamic) impedance is presented. The system enables to measure the dynamic impedance simultaneously at up to 16 frequencies from 1 to 400 kHz within 1 ms time slots. Repeating the measurements after predetermined intervals gives the results in the form of spectrograms. Experimental results characterizing the case of dynamic measurement of impedance variations caused by heart beating and breathing are given in the paper.