时频工具箱中计算群延迟的函数，语法格式：［gd,fnorm]=sgrpdlay(x),x是时域信号，fnorm返回频率坐标,gd返回估计出群延迟的输出向量．-frequency toolbox when calculating group delay functions, grammar format : [gd. fnorm] = sgrpdlay (x), x is the time domain signal to the frequency fnorm coordinates, gd t