ABSTRACT
The ability to apply excitation signals over a significant range of frequencies makes it possible to perform impedance spectroscopy in which the variation of impedance with frequency can be used as a discriminating factor for imaging. The distortion is not confined to the region of the movement as it is in photography. A pair-drive system, also called a single source system, applies currents between one pair of electrodes at a time and measures the voltages on the remaining electrodes. The voltage measurements can be done sequentially with a single voltmeter, though it is more common to measure the voltages in parallel using multiple voltmeters to reduce the data collection time. Pair-drive systems do not measure voltages on electrodes that are applying current while parallel-drive systems measure the voltages on all electrodes. The voltages measured on electrodes that are not injecting current are affected less by the contact impedance because of the high input impedance of the voltmeters.
