Influence of the multisine excitation amplitude design for biomedical applications using Impedance Spectroscopy

Electrical Impedance Spectroscopy (EIS) is a powerful tool to collect data from many biological materials in a wide variety of applications. Body composition fluid or tissue and organ state monitoring are just some examples of these applications. While the classical EIS is based on frequency sweep, the EIS technique using broadband excitations allows to acquire simultaneous impedance spectrum data. The strength and weakness of broadband EIS relies on the fact that it enables multiple Electrical Bio-Impedance (EBI) data collection in a short measuring time but at the cost of losing impedance spectrum accuracy. In general, there is a relationship between the broadband excitation time/frequency properties and the final EBI´s accuracy obtained. This paper studies the influence of the multisine broadband excitation amplitude´s design over the EBI accuracy by means of the resultant Noise-to-Signal Ratio (NSR) obtained when measuring with a custom impedance analyzer. Theory has been supported by a set of validation experiments.