说明：  用傅里叶变换对地震信号进行时频分析，通过修改参数可以深刻的认识傅里叶变换在时频分析中的意义，适合地震信号研究的初学者。
(Fourier transform of the seismic signal frequency analysis, parameter changes can be profound understanding of Fourier transform in the time-frequency analysis of significance for the seismic signals of beginners.)