信号在传输过程中会有噪声信号的加入，导致信号的幅值发生变化，从而对接收灵敏度造成影响。为了研究噪声与灵敏度之间的关系，采用两种信噪比计算方法，并通过对信号进行数字滤波、脉冲峰值提取和半幅点计算处理，进而完成DME（distance measuring equipment）信号的判决与灵敏度计算，并基于此分析DME判决与信噪比大小之间的关系。结果表明，在信噪比较小且信号强度足够小时，DME判决的准确性受噪声信号影响较大，从而会导致测距精度降低。

Noise signals are added to the signal during transmission, resulting in changes in the amplitude of the signal, thus affecting the reception sensitivity. In order to study the relationship between noise and sensitivity, two signal-to-noise ratio calculation methods were used, and digital filtering, pulse peak extraction and half-amplitude point calculation were processed on the signals, which in turn complete the judgment and sensitivity calculation of DME(distance measuring equipment) signals, and based on which the relationship between DME judgment and the size of signal-to-noise ratio was analyzed. The results show that when the signal-to-noise ratio is small and the signal strength is sufficiently small, the accuracy of the DME judgment is greatly affected by the noise signal, which will lead to the reduction of the ranging accuracy.