The signals were divided into segments and the frequency spectra were got and the frequency features were achieved and 4 types ofvariationoffrequency were found.
对微地震信号预分段，用小波提取其频率谱中的频率特征，得到了频率变化的四种趋势。
2
The variationoffrequency curve's mode peak content with the increasing of depth, shows not only the trend of chemical weathering but also variation gradient of weathering extent.
频率曲线众数峰含量随深度的变化，不但指示了化学风化趋势，而且反映了风化程度的变化梯度。
3
Generalized into local frequency from integral frequency, the method of joint time-frequency distribution effectively analyzes the signal based on the variationoffrequency with time.