说明：  短时傅立叶变换(STFT)源代码,用语非稳态信号的时频联合描述,可直接用于matlab程序之中.无解压密码.
(short-time Fourier transform (STFT) source code, the language of non-stationary signals to the joint time-frequency description, Matlab can be used directly in procedures. No extract passwords.)