Design Of Phase Difference Analysis Subsystem In BMIDS

The precision of phase difference is central to the technique of brain magneticinduction detection system. The technique is an advanced method which can reflect theelectrical conductivity of biological tissue by the measurements of the phase differencebetween the excitation signal and the detection signal in the magnetic-inductivemeasuring system. It is used to overcome the shortage in the current detectiontechnology of cerebral edema. As a result, the study of high precision phase differencehas great value to apply the BMIDS technology successfully in medicine.For the key technique of high-precision phase difference detection in the BMIDS, asoftware system design of detecting high-precision phase difference based on DSPprocessor was developed to improve the precision of phase difference andanti-interference in the BMIDS in the paper. At first, the paper introduces the cerebraledema detection system. Then, the present methods of phase difference detection areanalyzed to determine the best method. The factors influencing the precision of thephase difference detection are also analyzed, such as sampling points, sample frequency,window function and signal to noise ratio. And the precision requirement is determined.Finally, the software system for high-precision phase difference detection is realizedthrough the Visual Dsp++software platform.The experiment results indicate that the software system is fast, accurate andanti-disturbance. And the precision is controlled within0.005°. The high-precisionphase difference detection is successfully achieved.