磁共振成像系统中数字光纤传输技术研究

发布时间：2018-01-05 12:19

  本文关键词：磁共振成像系统中数字光纤传输技术研究　出处：《华东师范大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 磁共振成像 光纤 PCIE 数据传输

【摘要】：随着核磁共振成像技术的发展,磁共振接收机的通道数越来越多,对核磁共振数据传输的带宽、传输过程中数据的准确性等都有了更高的要求。在常规核磁共振系统中,扫描室与设备室之间通常用同轴电缆对模拟的核磁共振信号进行传输。同轴电缆在传输模拟信号的过程中存在损耗,并且多通道的射频电缆之间还会存在耦合,同时信号还会受到电磁波的干扰,从而导致核磁共振图像质量下降。基于上述同轴电缆传输过程中的一些不足,本文提出了 一种核磁共振数据数字光纤传输方案。在数字光纤传输方案中,由于数字光纤传输具有损耗小、受外界电磁波的影响小、频带宽、传输容量大等一些优点,因此数字光纤传输方案可以很好的解决同轴电缆在传输核磁共振信号过程中带来的问题,从而提高了图像的信噪比。在本文中通过对多种串行协议的分析,得出基于Seriallite协议的自定义数字光纤传输方案,在此协议中利用QUARTUS Ⅱ软件中的Mega Wizard Plug-In Manager工具生成的LPM_MUX IP核,实现核磁共振数据的复用和分接功能,并通过对ALTGXIP核进行配置实现时钟生成和恢复、8B/10B编解码、字节串化、字对齐处理、串并转换和差分电压控制等功能。另外还对高速收发器的重配置模块、时钟生成模块和逻辑控制模块进行了设计和配置。为了保证核磁共振系统激发信号和接收到的核磁共振信号具有相位相干性,首先必须使激发单元和接收单元参考同一个时钟源。本文利用了时钟数据恢复(Clock Data Recovery,CDR)单元,从输入串行的核磁共振数据流中恢复出时钟,保证了核磁共振数据发送端和接收端的参考时钟具有相位相干性,最终实现了数字光纤传输方案。在本方案中,通过 PCIE(Peripheral Component Interconnect Express)总线实现对核磁共振数据的读和写,并利用示波器和SignalTapⅡ逻辑分析仪对核磁共振数据进行了测试,并验证了数字光纤传输方案的时钟相干性和收/发数据的一致性。最终通过图像重建得到了人脑核磁共振图像,同时也验证了数字光纤传输方案的可行性。本文基于Seriallite协议,对核磁共振接收通道数据的传输格式进行了定义,传输实时性较高。利用时钟恢复单元不仅确保了时钟的相干性,且不需要专门的时钟传输通道,从而简化了电路结构。另外数字光纤传输方案的研究还为后续的数字光纤多模块级联传输奠定了基础,使得更多通道的磁共振数据在单根光纤上进行串行传输成为可能。
[Abstract]:With the development of nuclear magnetic resonance imaging technology, the number of channels in magnetic resonance receiver becomes more and more, and the bandwidth of nuclear magnetic resonance data transmission. The accuracy of the data in the transmission process has higher requirements. In the conventional nuclear magnetic resonance system. The simulated nuclear magnetic resonance (NMR) signal is usually transmitted by coaxial cable between the scanning room and the equipment room. There is loss in the transmission of analog signal and coupling between multi-channel RF cables. At the same time, the signal will also be interfered by electromagnetic wave, resulting in the quality of nuclear magnetic resonance image decline. Based on the above coaxial cable transmission process of some shortcomings. In this paper, a digital optical fiber transmission scheme for nuclear magnetic resonance data is proposed. In the digital optical fiber transmission scheme, due to the low loss of digital optical fiber transmission, the influence of external electromagnetic waves is small, and the frequency bandwidth is small. Some advantages such as large transmission capacity, so the digital optical fiber transmission scheme can solve the problem of coaxial cable in the process of nuclear magnetic resonance signal transmission. In this paper, through the analysis of various serial protocols, the self-defined digital optical fiber transmission scheme based on Seriallite protocol is obtained. In this protocol, the LPM_MUX IP core is generated by using the Mega Wizard Plug-In Manager tool in QUARTUS 鈪，

本文编号：1383096