Improvement of Electrical Bio-Impedance Measurement: Mixed Signal Approach

Abstract

This article deploys a 5-level shorten rectangular wave technique to measure lock-in electrical bio-impedance (EBI) in medical diagnosis. The new shorten rectangular EBI signal has better properties in eliminating odd harmonics compared to the conventional 3-level shorten rectangular wave technique. The results show that the measurement errors in the 3-component EBI are reduced about 0.3% for R, X, Z and 3% for Phase(Φ) when the 5-level signal is used instead 3-level signal.