对于信号发生器给出的方波信号作为待处理的信号，通过程序可以提取第一个脉冲，将后面的滤去。注意信号发生器给出的方波幅 值大概在3.3V左右，满足和FPGA的接口电平匹配。-The back of the filtered square wave signal given by the signal generator as a signal to be processed by the program can extract a pulse. Note that the square ampl