在某些物理实验中,往往需要从一长系列脉冲中取出一单个脉冲以作所需要的分析、测试之用。例如,在用ps高速扫描相机测量北京正负电子对撞机(BEPC)贮存环上同步辐射光脉冲时,由于用于启动相机扫描电路的触发脉冲与被测光信号均为周期信 In some physical experiments, it is often necessary to take a single pulse from a long series of pulses for the analysis and testing required. For example, in the use of ps high-speed scanning camera measuring Beijing BEPC storage ring synchrotron radiation pulse, as used to start the camera scanning circuit of the trigger pulse and the measured optical signal are periodic letter