语音信号是一个非平稳时变的信号，所以用计算稳态信号的方法计算功率谱密度函数没有太大意义，看不出信号的动态变化，"gonglvpu"给出计算短时功率谱密度函数(Speech signal is a non-stationary time-varying signal, so it is not very meaningful to calculate the power spectral density function by calculating the steady-state signal. The dynamic changes of the signal can not be seen. The "gonglvpu" gives the short-term power spectral density function.)