Measurement Of Bio-impedance Spectroscopy And It's Application In Study Of Channel And Collateral

Bio-impedance measurement as one of the noninvasive technologies has a bright future in physiology and pathology, especially in the field of Channel and Collateral impedance study. Bio-impedance measurement is developing from single frequency to spectroscopy, bio-impedance spectroscopy has more value in use.Two bio-impedance measurement systems are developed in this paper. Systemâ… and Systemâ…¡.Systemâ… is the orthogonal demodulation system, it uses DDS to produce orthogonal sinusoidal signals. Orthogonal signals change to current signals trough the voltage to current circuit. It is input to body by the two input probes, the output signal from the output probes is demodulated, filtered, amplified, then the impedance signal will be gotten.Systemâ…¡is based on impedance converter AD5933. The SOC newly produced by ADI is used. All main parts of bio-impedance measurement are included in this single chip. It has a very small volume and extraordinarily simple circuit. This system can not only be used alone, but also can be chosen to be controlled by PC. It is very easy to operate.Experiment on the effect of different manipulations is carried out with Systemâ…¡. There are all together four manipulations are experimented. The result shows that all four manipulations can low the impedance of Channel and Collateral, the difference is durative time and extent. For the swatch is not enough, the individual variance is high, more experiments are needed.