论文部分内容阅读
本文对连续波式核磁共振仪的前置级——边缘振荡器的性能进行了理论分析。作者对场效应管采用了五次多项式转移特性及双噪声电流源模型,从而解决了振荡器振荡幅度、振幅对电导的变化率、包络检波后的核磁共振信号、噪声及输出信噪比的计算。首次从理论上证明了边缘振荡器可能存在一个最佳工作点,使输出信噪比达到极大值。文中给出的实测结果说明理论与实验基本符合。本文的结果为边缘振荡器最佳工作状态调节及合理使用提供了理论依据。
In this paper, the theoretical analysis of the performance of the pre-stage-edge oscillator for continuous-wave NMR was carried out. The author used the quintic polynomial transfer function and dual-noise current source model to the FET to solve the oscillation amplitude of the oscillator, the rate of change of the amplitude to the conductance, the NMR signal after the envelope detection, the noise and the output signal-to-noise ratio Calculate. For the first time, it is theoretically proved that the edge oscillator may have an optimum operating point, and the output signal-to-noise ratio reaches a maximum value. The experimental results given in this paper show that the theory and experiment are basically in line with each other. The results of this paper provide a theoretical basis for the optimal operation of the edge oscillator and rational use.