【摘要】 短时Fourier变换(STFT)在分析非平稳信号的过程中,受调制系数的影响,时频分布图中的能量扩散至主导频率的周围,降低了时频分布的可读性.运用STFT分析瞬时频率缓变或恒定的信号时,调制系数的影响较小甚至可以忽略不计,而得到能量聚集程度很高的时频分布.根据这一特点,提出了迭代广义短时Fourier变换(IG-STFT),该方法有效改善了时频图的可读性.首先运用迭代广义解调分离出频率恒定的单分量成分,然后运用STFT分析信号的时频分布,最后依据STFT的分析结果和相位函数得到原信号的时频分布.通过行星齿轮箱仿真信号和实验信号分析,验证了该方法在分析非平稳信号中的有效性,准确诊断了齿轮故障.更多还原

【Abstract】 Due to the effect of the modulation part,the energy diffuses around the surrounding area of dominating frequencies and diminishes the readability of the time-frequency representation when short-time Fourier transform( STFT) is used to process nonstationary signals. However,when the instantaneous frequency slowly changes or is constant,the effect is small and can even be neglected. Thus,the time-frequency representations have high-energy concentration. Based on this feature,a novel method called iterative generalized short-time Fourier transform( IG-STFT) was proposed,which improved the readability of the time-frequency representation. First,the stationary mono-components are separated using iterative generalized demodulation. Then,the time-frequency representations of each mono-component are acquired using STFT. Finally,the time-frequency representation of the original signal is obtained according to the analysis results of STFT and the phase function. The analysis results of a planetary gearbox simulation signal and experimental signals verify the effectiveness of this method for analyzing nonstationary signals and diagnosing gear faults.更多还原