| Magnetic Induction Tomography (MIT) is a new method non-contact method of conductivity tomography. In the excitation magnetic field, the biologic tissue inspires perturbation for electric magnetic induction, and the perturbation could be measured by receiver coils. The detecting of high-frequency is one of key problems of MIT. For the characteristics of MIT signal, in this paper, a MIT high-frequency magnetic induction signal acquisition system by FPGA was designed, and the system suits for high-frequency weak signal detecting with high signal acquisition performance. Some main works and conclusions are as following:(1) Biomedical Electromagnetic, eddy-current testing and conductance tomography were studied as the basic theory, and MIT principle was researched through mathematic and experimental model.(2) A high frequent (10MHz) sine signal generator was designed which was used as exciting source.(3) The new 12 coils exciting-measuring model of MIT was proposed, which included the selected principles and the array of coils in the paper.(4) The rotating plat was droved by step motor, and the detected object was rotated in the imaging system, in order to get more data of different detecting orientation.(5) A MIT high-frequency magnetic induction signal acquisition system by FPGA was designed, and then high frequent induction signal was detected and transmitted from detecting coils.The NaCl solution with an aluminum bar was used as detecting object in this paper, and experiment results demonstrated that the model and the detecting system were effective in high-frequency weak signal detecting, and the conductivity of different objects can be distinguished, and it satisfied the requirements of high-frequency Magnetic induction signal detecting. |
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