用于提取语音信号的能量谱的函数,ampp(s,a,b,c)，x为输入信号，a,b,c用于指定subplot函数的作图位置-A function for extracting the energy spectrum of the speech signal, ampp (s, a, b, c), x is the input signal, a, b, c is used to specify the location of subplot mapping function