该列有很多重复的值（频率统计信息），或者该列的值分布不均匀，即它们在某些局部是聚合的（分位数统计信息）。
The column has many duplicates (frequency statistics), or the values of the column are not evenly distributed, which means they are clustered in certain areas (quantile statistics)
索的局部振动虽然对结构主要振型的频率影响不大，但对振型能量分布有比较明显的影响。
Cable local vibration has little effect on the modal frequency, but more on the modal energy distribution.
联合时频分布方法把整体频谱推广到局部频率，根据频率随着时间的变化情况，对信号进行有效的分析。
Generalized into local frequency from integral frequency, the method of joint time-frequency distribution effectively analyzes the signal based on the variation of frequency with time.
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