基于瞬时转速的变窗STFT变换

刘小峰;柏林;秦树人

振动与冲击 ›› 2010, Vol. 29 ›› Issue (4) : 27-29,5.

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振动与冲击 ›› 2010, Vol. 29 ›› Issue (4) : 27-29,5.
论文

基于瞬时转速的变窗STFT变换

  • 刘小峰; 柏林; 秦树人
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Rotating Speed Based Variable Window STFT

  • LIU Xiaofeng; BO Lin ;QIN Shuren
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文章历史 +

摘要

针对旋转机械振动信号的非平稳特性及其与转速变化之间的关系,发展了一种基于可变窗短时傅立叶变换(STFT)的精细时频分析方法。该方法首先根据转速曲线的斜率变化规律对转速曲线进行了最优分段,并对每个时间段内的转速数据进行二次曲线拟合;继而在拟合参数的基础上,对STFT移动窗的窗型及窗长进行设计计算;然后根据转速曲线的时间分段点将被分析的旋转机械信号分割成相应时间段内的子信号,再采用每个时间段内设计的窗函数对每个子信号分别进行STFT变换,并把每个时段上求得的时频分布拼接成被分析信号的整体时频谱。仿真和应用试验表明,采用这种基于瞬时转速的新型时频变换,能够得到较理想的时频分辨率,非常适合于旋转机械信号的精细时频分析,具有良好的研究价值和发展前景。





Abstract

According to the nonstationarity of rotatary machinary viberating signal and its relationship to rotating speed, a novel elaborate time-frequency(TF) analysis based on variable window Short Time Fourier Transformation(STFT). Firstly, the rotaing speed curve is optimally segmented according to its slope change, and every segment is fitted using quadratic polynomial. Secondly, based on the fitting parameters the shape and length of moving window are designed respectively. Thirdly, the viberation signal is divided at the segmenting time points obtained above-mentioned, then each signal subsegment is processed using STFT with corresponding window shape and length designed. Finally, the whole TF distribution is obtained by concatenating the subsegment TF spectrum. The simulation and experiment results indicate that the STFT with variable window based on instantenous rotaing speed is very adptable to fine time-frequency analysis for rotary machine viberation signal. It has good research value and application prospects.

关键词

非平稳信号 / 转速曲线 / 短时傅立叶变换 / 可变窗 / 时频分布

Key words

non-stationary signals / rotating speed curve / STFT / variable window / time-frequncy distribution

引用本文

导出引用
刘小峰;柏林;秦树人. 基于瞬时转速的变窗STFT变换[J]. 振动与冲击, 2010, 29(4): 27-29,5
LIU Xiaofeng;BO Lin;QIN Shuren. Rotating Speed Based Variable Window STFT[J]. Journal of Vibration and Shock, 2010, 29(4): 27-29,5

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