Analysis of guided wave signal based on LabVIEW and STFT

Ultrasonic guided wave signal is a dynamic non-stationary. There is a serious phenomenon of frequency dispersion in it. Use of traditional time-domain and frequency domain analysis methods can not reveal the characteristics of spectral change over time. So, we Study the characteristics of the signal characteristics of guided waves, describe the time-frequency analysis theory of short-time Fourier transform (STFT), and realize the STFT algorithm and digital filtering based on LabVIEW software. Carried out STFT and time-frequency spectrum analysis for the guided wave in the steel. And find that frequency components in it change over time. Analysis the mode conversion phenomena of a guided wave, it can more Accurate position the defects. The results show that, when the communication distance is far, STFT can be used for its dynamic signal spectrum analysis and pattern recognition, and using the virtual instrument technology. It will have greater application prospects.