对应不同的a值产生一组矢量来表示高斯脉冲波形，并计算其相应的ESD。最后，画出了各个a值所对应的脉冲波形及其ESD-a different corresponding values of a group vector to express Gaussian pulse waveform, and calculated the corresponding ESD. Finally, paint all of a value corresponding to the pulse waveform a