A study of bispectral analysis in gearbox condition monitoring is presented.The theory of bispectrum and quadratic phase coupling (QPC) is first introduced, and then equationsfor computing bispectrum slices are obtain...A study of bispectral analysis in gearbox condition monitoring is presented.The theory of bispectrum and quadratic phase coupling (QPC) is first introduced, and then equationsfor computing bispectrum slices are obtained. To meet the needs of online monitoring, a simplifiedmethod of computing bispectrum diagonal slice is adopted. Industrial gearbox vibration signalsmeasured from normal and tooth cracked conditions are analyzed using the above method. Experimentsresults indicate that bispectrum can effectively suppress the additive Gaussian noise andchracterize the QPC phenomenon. It is also shown that the 1-D bispectrum diagonal slice can capturethe non-Gaussian and nonlinear feature of gearbox vibration when crack occurred, hence, this methodcan be employed to gearbox real time monitoring and early diagnosis.展开更多
目的:在双谱域定义一种单通道脑电(electroencephalogram,EEG)睡眠分期特征提取方法,为实现自动睡眠分期提供新的思路。方法:基于麻醉深度检测的脑电双频指数(bispectral index,BIS)子参数快慢同步比的定义,结合睡眠各期双谱图和EEG特...目的:在双谱域定义一种单通道脑电(electroencephalogram,EEG)睡眠分期特征提取方法,为实现自动睡眠分期提供新的思路。方法:基于麻醉深度检测的脑电双频指数(bispectral index,BIS)子参数快慢同步比的定义,结合睡眠各期双谱图和EEG特征节律波频带范围,定义6种快慢同步比计算公式。选取2名受试者整夜睡眠EEG数据,以30 s EEG信号为一个样本,根据不同公式计算睡眠各期快慢同步比并进行统计学分析,得出最优定义下的计算公式。增加其他9名受试者,计算其睡眠各时相快慢同步比,进行统计学分析,进一步验证该特征的睡眠分期效果。结果:每名受试者睡眠五期快慢同步比组间差异有所不同,但大多有显著统计学意义。结论:双谱域定义的快慢同步比可用于睡眠分期,且具有普遍性,可作为研究睡眠自动分期的一种重要特征。展开更多
So far, the problem of the harmonic retrieval with quadratic phase coupling in mixed noises has not been resolved well. For this reason, this paper, based on the third , forth order cumulants and Hilbert transform, ...So far, the problem of the harmonic retrieval with quadratic phase coupling in mixed noises has not been resolved well. For this reason, this paper, based on the third , forth order cumulants and Hilbert transform, proposes a new method named HBTFCH SVD TLS.The method can realize harmonic retrieval in mixed noises even when the harmonic signal includes the components of quadratic phase coupling.Simulation results show the effectiveness of the method.展开更多
This paper presents a new method based on ESPRIT for estimating the quadrati-cally coupled frequency pairs (QC pairs). This method constructs an ESPRIT matrix pencil by exploiting frequency symmetry property of comple...This paper presents a new method based on ESPRIT for estimating the quadrati-cally coupled frequency pairs (QC pairs). This method constructs an ESPRIT matrix pencil by exploiting frequency symmetry property of complex third-order cumulants, QC pairs are yielded by evaluating the generalized eigenvalues of this matrix pencil. A simple analysis is provided to show the method is simpler. The accuracy and the high-resolution performance of this method are verified by simulations.展开更多
基金This project is supported by 95 Pan Deng Program of China (No.PD952l908) National Key Basic Research Special Foundation of China (No.Gl998020320)Provincial Natural Science Foundation of Hubei, China (No.2000J125)
文摘A study of bispectral analysis in gearbox condition monitoring is presented.The theory of bispectrum and quadratic phase coupling (QPC) is first introduced, and then equationsfor computing bispectrum slices are obtained. To meet the needs of online monitoring, a simplifiedmethod of computing bispectrum diagonal slice is adopted. Industrial gearbox vibration signalsmeasured from normal and tooth cracked conditions are analyzed using the above method. Experimentsresults indicate that bispectrum can effectively suppress the additive Gaussian noise andchracterize the QPC phenomenon. It is also shown that the 1-D bispectrum diagonal slice can capturethe non-Gaussian and nonlinear feature of gearbox vibration when crack occurred, hence, this methodcan be employed to gearbox real time monitoring and early diagnosis.
文摘目的:在双谱域定义一种单通道脑电(electroencephalogram,EEG)睡眠分期特征提取方法,为实现自动睡眠分期提供新的思路。方法:基于麻醉深度检测的脑电双频指数(bispectral index,BIS)子参数快慢同步比的定义,结合睡眠各期双谱图和EEG特征节律波频带范围,定义6种快慢同步比计算公式。选取2名受试者整夜睡眠EEG数据,以30 s EEG信号为一个样本,根据不同公式计算睡眠各期快慢同步比并进行统计学分析,得出最优定义下的计算公式。增加其他9名受试者,计算其睡眠各时相快慢同步比,进行统计学分析,进一步验证该特征的睡眠分期效果。结果:每名受试者睡眠五期快慢同步比组间差异有所不同,但大多有显著统计学意义。结论:双谱域定义的快慢同步比可用于睡眠分期,且具有普遍性,可作为研究睡眠自动分期的一种重要特征。
文摘So far, the problem of the harmonic retrieval with quadratic phase coupling in mixed noises has not been resolved well. For this reason, this paper, based on the third , forth order cumulants and Hilbert transform, proposes a new method named HBTFCH SVD TLS.The method can realize harmonic retrieval in mixed noises even when the harmonic signal includes the components of quadratic phase coupling.Simulation results show the effectiveness of the method.
文摘This paper presents a new method based on ESPRIT for estimating the quadrati-cally coupled frequency pairs (QC pairs). This method constructs an ESPRIT matrix pencil by exploiting frequency symmetry property of complex third-order cumulants, QC pairs are yielded by evaluating the generalized eigenvalues of this matrix pencil. A simple analysis is provided to show the method is simpler. The accuracy and the high-resolution performance of this method are verified by simulations.
