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Title:: Preliminary Research of Phase Demodulation of Magnetic Induction Tomography(MIT) based on Digital Signal Processor

Author(s):: JING Yufei; LIU Ruigang; Department of Medical Imaging, School of Biomedical Engineering, Fourth Military Medical University, Xi’an 710032, China

Keywords:: Magnetic induction tomography; Phase demodulation; Digital signal processor（DSP）; Data transmission; Orthogonal sequence; Coefficient of correlation

摘要:: 在硬件端完成MIT测量数据的相位解调以期降低硬件与计算机间的数据传输负担和减少相位检测时间。通过对数字信号处理器（DSP）芯片的编程，实现正交序列相位解调算法，并分别对两路无噪声仿真信号和由任意波形发生器产生的实际信号进行相位解调。两种模拟MIT测量信号的相位解调结果与设定相位差的相关系数均超过0.998，单次鉴相耗时约为0.048 s。基于DSP的MIT相位解调方法有效可行。

Abstract:: To relax the burden of data transmission from the hardware to the computer and decrease the time of detecting phase shift by demodulating the measured data of MIT in hardware. The orthogonal sequence phase demodulation algorithm was programmed in the Digital Signal Processor(DSP). Two simulated signals without noise and two real signals from the arbitrary function generator were demodulated, respectively. The correlation coefficients of two kinds of MIT measured signal was over 0.998. The time of once phase demodulation was about 0.048 s. Phase demodulation in DSP is feasible and valid.