RESUMO
The electrical impedance of tissue can give important informations about the viability of the tissue. A non-invasive and contact-free measuring system using an inductive sensor is presented. Using a single pick-up coil the system is not sensitive enough for measuring the small changes in conductivity of biological tissue. Employing a gradiometer instead of a single pick-up coil can improve the resolution of the system. The developed data acquisition system is realized using four parts: A lock-in-amplifier, providing a sinusoidal signal and measuring the signal of the sensor, a power amplifier, driving the excitation coil of the sensor, the inductive sensor and a preamplifier for buffering a reference signal and amplifying the output signal of the sensor. In this paper the focus is on the hardware that was set up. Results of measurements on inhomogeneous phantoms are shown.
