爆破震动信号的时频分析

针对具体的爆破震动信号,基于短时Fourier变换(STFT)、连续小波变换(CWT)、离散小波变换(DWT)和Hilbert-Huang变换(HHT)进行时频分析比较研究。结果表明:STFT使用的窗函数固定,分辨率单一,其分析结果只能大致反映信号能量随时间的变化;小波变换(WT)以小波基为变换基础,具有多分辨率特点,其分析结果较详细地反映了质点震动强度随时间的衰减起伏变化,但小波谱的能量在频率范围内分布较宽;HHT自适应性强、高效,Hilbert能量谱能清晰地表明能量随时频的具体分布,并且大部分能量都集中在有限的能量谱线上。分析认为HHT是一种全新而更优越的分析与处理爆破震动信号的时频方法。

Time-frequency analysis of blasting vibration signals

A recorded signal of blasting vibration was analyzed in time and frequency domain by means of short time Fourier transform(STFT),continuous wavelet transform(CWT),discrete wavelet transform(DWT) and Hilbert-Huang transform(HHT).The analyzed results from STFT with fixed window function and single resolving power could only reflect how the signal energy varied with time approximately and results from wavelet transform(WT) based on wavelet base function and with multi-resolving power could display the attenuation of particle oscillatory intensity in time domain.EMD was a good self-adaptive and effective method,with which Hilbert energy spectrum could clearly express the variation of energy with time and frequency in detail,and most energy was concentrated in a definitive range of time and frequency,but that of wavelet spectrum lines were distributed in a wider frequency range.Therefore HHT was a kind of new time-frequency method for analyzing and processing the blasting vibration signals.