Design on some modules of permanent magnet MRI

采用核磁共振技术能够快速、准确、清晰的获得物质的内部结构信息。利用该技术研制的核磁共振成像仪不同于其它的成像技术（如CT等），在没有对机体产生损伤的同时，可以直接给出横断面、矢状面、冠状面以及各种斜面的体层图像。其中，开放式永磁型核磁共振成像仪由于其价格便宜、维护简单，在医学检测中发挥着越来越大的作用。但是，由于商用化的核磁共振成像仪基本上由国外少数几家公司生产，核心技术被国外公司垄断，导致国内销售的成像仪价格过高。因此，研制具有自主产权的核磁共振成像仪有着极其重大的意义。 本文以开放式核磁共振成像仪的研制为研究背景，重点论述了其中几个重要模块的软硬件设计，主要工作内容如下： 1、数据传输...The nuclear magnetic resonance can obtain the information of sample’s internal structure rapidly and accurately.Compared to other medical imaging equipment,The Magnetic Resonance Imaging can give transaxial, coronal and sagittal sections without damaging of organism.Because of low prices and easy maintenance,the open permanent magnet type of MRI is more and more important in medical examination...学位：工学硕士院系专业：物理与机电工程学院_电磁场与微波技术学号：1982011115285

Design of NMR receive channel based on STM32

针对核磁共振波谱仪中接收通道的功能需要,提出了一种基于STM32作为协处理器,通过移植lWIP协议栈,实现数据流直接多通道网络传输的设计方案。该方案和以往方案相比,大大减轻了主处理器fPgA的工作负担,并且具有实时性高、模块化、易于拓展等特点。主要介绍了该方案的主要设计思路以及软硬件基本架构,重点阐述了其中的关键技术,实物完成后通过nETIO以及系统联机测试的结果表明本方案满足波谱仪接收通道的实际性能需要,同时使得系统的可维护性得到了提高。To satisfy the require of the receiver channel,this paper puts forward a designing program which uses STM32as a co-processor and LwIP as a protocol stack to achieve multichannel data transmission.Compared to the previous programs,this program greatly reduces the workload of the host processor FPGA,It is high real-time,modular and easy to expand.The paper will introduce the software and hardware platform of this program and the key of techniques.The result based on netio and on-line testing proves that this program meets the requirement of receiver channel and improves the manufacturing and maintainability of the system

Design of NMR transmit pulse waveform based on FPGA

基于任意波形发生器的原理,采用ddS(dIrECT dIgITAl SynTHESIS)技术,以单片机控制芯片STC89lE51和fPgA芯片XC5VfX70T为基础进行硬件和逻辑设计,使用ISE10.1和MOdElSIM软件编写脉冲波形发生器的各个子模块和测试模块,利用上位机软件或者键盘模块进行设置,改变波形频率和相位,最终产生核磁共振谱仪所需的调频调相波形数据。仿真结果表明,该方案产生的信号波形可灵活实现频率和相位的更改,波形性能良好,对于核磁共振谱仪发射脉冲波形的设计提供了可靠的方法和思路。The hardware and logic design based on MCU control chip STC89LE51 and FPGA chip XC5VFX70T combines the principle of the arbitrary waveform generator with DDS(direct digital synthesis) technology.The sub-modules of pulse waveform generator and test modules are designed by ISE10.1 and Modelsim.Using the PC software or keyboard to set the frequency and phase of waveform,the ultimate frequency modulation and phase modulation waveforms data required by the NMR spectrometer can be generated.The simulation results show that the signal waveform designed by the program can have a good performance in the change of frequency and phase,providing reliable methods and ideas for the design of the transmit pulse waveform in the NMR spectrometer.国家自然科学基金(11175149)资助项