小型核磁共振仪探头及低噪声放大器的设计与实现

Design and Realization of the NMR Probe and Low Noise Amplifier

分析了核磁共振(NMR)探头的物理原理,设计并实现了一种应用于小型核磁共振系统的探头和低噪声放大器.分析了以往探头制作过程中存在的各种问题,提出了一种利用阻抗变换求解分立元件参数的方法,该方法克服了以往探头制做时只凭经验匹配元器件的弊端.本文设计并实现的前端低噪声放大器主要由核心元件ATF10136及其旁路网络组成,整个电路的噪声系数只有0.6.探头的实测数据与理论分析结果相吻合,信号处理结果证明低噪声放大器的设计是十分成功的.

The physical principle of NMR antenna was analyzed, the probe and low noise amplifier was designed.We have discussed the problems existed in the ancient manufacture process of probe, and proposed an impedance transform method to calculate the coefficient of every component, it has overcome the disadvantage of traditional method in producing probe which mainly depends on experience. The low noise amplifier circuit has a noise coefficient about 0.6. The final test accords with the theoretical results exactly ...