Short-time fourier transform of continuous wave doppler signals

摘要

A Doppler-based ultrasonic monitoring scheme was introduced to detect discontinuities on the surface of a rapidly moving object. Single-tone, continuous wave (CW) ultrasound was impinged onto the moving surface and the reflected signal was processed by a Short-Time Fourier Transform (STFT) algorithm to identify surface anomalies. By monitoring the peak magnitude of the STFT spectra within a specified window, it was possible to reconstruct a signal representing Doppler frequency shift continuously in the time domain.