The Design of Four-channel Receiver in 0.5T MRI System for Joints

磁共振成像仪器以磁共振成像理论和技术为基础，是组织无损成像的重要手段。历经四个主要发展阶段，被广泛应用于科学、医疗等多个领域，关乎国计民生。中国是世界上最重要的磁共振成像仪市场之一，但研发实力仍落后于先进水平。为了改变这一现状，国家加大了对成像仪的研发投入力度。 本论文重点着眼于研制“0.5T磁共振关节成像仪”的关键部件之一：四通道数字接收机。接收机吸收软件定义无线电架构，采用数字直接下变频接收方案，便于仪器小型化、数字化。其主体由时钟模块、AD6620子系统、DSP（DigitalSignalProcessor）子系统和FPGA（Field-ProgrammableGateArray）子系...MRI (Magnetic Resonance Imaging) instrument, which is based on magnetic resonance imaging theorems and technologies, is significant at tissue lossless imaging field. After four main development phases, it is now widely used in scientific research and medical treatment, beneficial to country’s bloom and people’s livehood. Although China is the most important market of MRI instrument, the referenced...学位：工程硕士院系专业：物理科学与技术学院_工程硕士(电子与通信工程)学号：3332014115284

Design of MRI communications and pulse generation module

针对小型化核磁共振成像仪主控板的功能需要提出新的设计方式,采用FPGA开发板作为主控板,以Nios II嵌入式软核作为协处理器,通过在其上移植μC/OS-Ⅱ操作系统及lwIP协议栈,实现与计算机的网络通信;使用Verilog硬件描述语言编写脉冲序列生成模块,实现对指令的解析以及执行,形成用户要求的脉冲序列。最终测试结果表明,主控板的通信速率以及通过示波器采集得到的脉冲序列均满足成像仪系统要求。而且这种软硬结合的设计方式与以往全软件的设计相比,使成像仪精度更高,性能更加稳定。To satisfy the require of the MRI main control board,this paper puts forwards a new design which uses FPGA development board as main control board and uses Nios II as a co-processor.We transplant theμC/OS-II operating system and protocol stack lwIP to achieve the network communication with computers.Then we use the hardware language Verilog to write pulse sequence generation module to achieve the analysis and execution of the command.Eventually it produces user's pulse sequence.Final test results show that the communication rate of the main control board and pulse sequence which is obtained by oscilloscope can satisfy the requirements of the MRI system.Compared with the past of the whole software design,this design make the MRI system higher precision and more stable.国家自然科学基金(11175149)资助项