An Analysis of the Wave Propagation of a Structure Based on STFT, Higher Order Time-frequency Analysis and Wavelet Transform

STFT, 고차위그너분포 및 웨이브렛 변환 기술을 이용한 탄성파 추적

There has been a number methods for the presentation of time-frequency analysis of non-stationary signal. In this paper, STFT(short time Fourier transform), wavelet transform, Wigner distribution, and higher order Wigner distribution are discussed in details with simulation signals. They are also applied to the analysis of the wave propagation of a semi finite beam. Wigner distribution and higher order Wigner distribution have good time-frewuency resolutions. Wavelet transform is required for impact analysis but should be applied carefully. STFT suffers from time-frequency resolutions. Each method is has its advantage and disadvantage depending on each application signals.