核磁共振成像系统接收端数字化研究

Research on Digital Receiver in MRI System

国内目前的核磁共振的关键设备—谱仪具有相位不稳,成像不够清晰,分立元件过多,升级困难的缺点。针对这些缺点对谱仪的模拟接收端提出了数字化接收方案。该方案克服了模拟电路为主的射频接收端所存在的问题,抗噪声干扰力强,稳定性高。还对ADC采样率的选择作了详细的分析。该方案经实验仿真证明具有可行性。

Analog receiver of MRI has many disadvantages:it can't get steady phases and clear images, and it can't be upgraded easily. Digital receiver can overcome all of these problems. A structure of digital receiver of MRI is proposed. By using this digital stucture, MRI can solve the problems which appear in the structure of analog one. At the same time, digital structure of receiver can reject noise strongly and get high steady phases; moreover, it can be upgraded easily. The sampling frequency in ADC is also mentioned. The results of simulations and experiments have proved that the technique and system are feasible and effective.