针对实验中同一微光像增强器的信噪比在装配自动门控电源后有偏低现象，从而开展了以下研究：首先通过借鉴微光像增强器的信噪比公式，理论推导分析了阴极高压脉冲对信噪比的影响；其次分别给微光像增强器光电阴极施加高压脉冲和直流高压，通过实际测量两种状态下的信噪比，来验证理论推导分析的正确性；最后提出了一种自动门控电源阴极高压脉冲控制电路的设计方法，解决了基于自动门控电源的微光像增强器测试时的信噪比偏低问题。

Aiming at image intensifier SNR degradation after auto gated power supply assembled, the following research work were carried out. First, the image intensifier SNR formula is used to analyze the effect that cathode high voltage affects the intensifier SNR. Two different cases of intensifier SNR are measured: cathode high voltage pulse and cathode DC high voltage. Then two kinds of cases are analyzed and compared. At last, this paper concludes the research and points out a new method of designing the cathode start control circuit with auto-gating power supply.