感应式磁声耦合成像脉冲磁场激励源的设计

Design of Exciting Source for Pulsed Magnetic Field Used in MAT-MI System

目的:脉冲磁场激励源是感应式磁声耦合成像系统激发声振动信号的关键部分,为了提高成像质量及成像分辨率,对脉冲磁场激励源进行参数设计及模拟实验验证。方法:选用正弦脉冲作为激励信号,对脉冲磁场放电电路参数进行了仿真设计,通过实验测量磁激励线圈产生的空间磁场信号,验证仿真结果。结果:实验结果表明,利用正弦脉冲对设计制作的线圈进行放电,磁感应强度信号中心频率为0.8MHz,频带宽度为1.2MHz,此参数下成像分辨率理论上可达1.9mm,脉宽达1.27μs。结论:利用设计的脉冲磁场激励源参数,通过功率放大即可实现感应式磁生耦合成像系统的脉冲磁场激励。

Objective To carry out parameter design and simulation experiment for the exciting source of the pulsed magnetic field so as to improve the imaging quality and resolution by the MAT-MI system. Methods The sinusoidal pulse was adopted to generate exciting pulse and the parameter of the discharging circuit of the magnetic generator was simulated. Experiment was carried out to validate the simulation results. Results Experiments showed that the centre frequency of the inducted magnetic pulse was 0.8MHz, the bandwidth 1.2 MHz and the pulse width 1.27 μs. Conclusion Using the designed parameters of the pulsed magnetic field, the MAT-MI system can be excited through power amplification.