基于Gabor重构的发动机振声信号阶次分量瞬时幅值的提取
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摘要
从数值试验中总结了高斯窗STFT幅值谱对阶次分量的分隔能力与连续时间域内高斯窗的时间宽度之间的定量关系,并指出STFT幅值谱的阶次切片做为瞬时幅值估计所存在的问题。论述了Gabor阶次波形重构技术有效的前提条件,并基于确立的高斯窗宽与STFT幅值谱对阶次分量的分隔能力之间的关系,提出了一种改进的Gabor阶次波形重构流程,该流程摒弃了试凑分析参数的模式。仿真表明重构的阶次波形经Hilbert变换得到的包络可以做为瞬时幅值的有效估计。
The relationship between the Gaussian window's time standard deviation in the continuous time domain and the ability of the short time fourier transform(STFT) amplitude spectrum with Gaussian window to separate order components was established quantitatively according to numerical experiments.The problems in taking the order slices of the STFT amplitude spectrum as the instantaneous amplitude estimates were pointed out.The premises for successful Gabor order waveform reconstruction were examined.An improved flowchart for Gabor order waveform reconstruction,which abandons the try-and-error mode in choosing the analysis parameters,was formulated based on the established relationship mentioned above.Simulations show that the envelope obtained from the Hilbert transform of the reconstructed order waveform acquired by employing the improved flowchart can be used as a valid instantaneous amplitude estimate.
The relationship between the Gaussian window's time standard deviation in the continuous time domain and the ability of the short time fourier transform(STFT) amplitude spectrum with Gaussian window to separate order components was established quantitatively according to numerical experiments.The problems in taking the order slices of the STFT amplitude spectrum as the instantaneous amplitude estimates were pointed out.The premises for successful Gabor order waveform reconstruction were examined.An improved flowchart for Gabor order waveform reconstruction,which abandons the try-and-error mode in choosing the analysis parameters,was formulated based on the established relationship mentioned above.Simulations show that the envelope obtained from the Hilbert transform of the reconstructed order waveform acquired by employing the improved flowchart can be used as a valid instantaneous amplitude estimate.
引文
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[2]孔庆鹏,宋开臣,陈鹰.发动机变速阶段振动信号时频分析阶比跟踪研究[J].振动工程学报,2005,18(4):448-452.
[3]郭瑜,秦树人.基于瞬时频率估计及时频滤波的阶比分量提取[J].中国机械工程,2003,14(17):506-1509.
[4]田昊,唐力伟,田广,等.基于核独立分量分析的齿轮箱故障诊断[J].振动与冲击,2009,28(5):163-164.
[5]Qian S.Gabor expansion for order tracking[J].Sound andVibration,2003,37(6):18-22.
[6]Shao H,Jin W,Qian S.Order tracking by discrete Gaborexpansion[J].IEEE Transactions on Instrumentation andMeasurement,2003,52(3):754-761.
[7]Qian S,Chen D.Discrete Gabor transform[J].IEEE Trans.Signal Processing,1993,41(7):2429-2439.
[8]Qian S.Introduction to time-frequency and wavelet transforms[M].Upper Saddle River,NJ:Prentice Hall PTR,2002:41-72.
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