Sensitivity Analysis of the Simply Noise-matched Receiving Coil for NMR Experiments

The article analyzes the sensitivity of unmatched receiving coil for the NMR scanner. Receiver of the scanner was investigated from the point of view of noise features. Theory of the noise figure has been modified to utilize the receiver for digitization of its own noise and the noise figure calculation. The resulting noise figure has been measured with different source impedances and the optimal value has been acquired. Influence of the noise figure on the resulting signal-to-noise ratio has been calculated for the sensitivity judgement. The output SNR has been investigated for constant input SNR as well as for constant input voltage. Many results are depicted in figures. Also examples of theoretical results are depicted graphically.