对非平稳信号进行分段、截取，再做短时傅里叶变换，分析其频谱特性，并找到各个时间节点的频率特性，以便分析不同事件段内的声音特征。(The non-stationary signals are segmented and intercepted, and then the short-time Fourier transform is used to analyze their frequency spectrum characteristics, and the frequency characteristics of each time node are found in order to analyze the sound characteristics in different event segments.)