ABSTRACT
ABSTRACT: Classically bioimpedance measurements are performed by injecting cur rent into the tissue under investigation, and raw data is acquired as measured response volt age. While it is relatively easy to design an optimized current source for single frequency or narrow bandwidth measurements, things are considerably more difficult when broadband spectroscopic measurements are required. Active current sources work reasonably well up to some megahertz, but unfortunately their parameters degrade significantly at higher frequen cies. Working range of passive or purely resistive current sources on the other hand, while not comparable at lower frequencies can reach potentially higher frequencies. Imperfections caused by limited output impedance can be compensated by performing simultaneous cur rent measurements. Comparison of three designs is given, results analyzed, and practical circuit tested.
