Fast realization of zoom-spectrum wigner-ville distribution analysis in a narrowband

Doppler information of line spectrum can be used to estimate the parameters of radiated noise sources on underwater target. Because of the low frequency and low speed characteristics, the Doppler frequency shift changes weakly. Its time-frequency analysis should be limited in a selected narrow-frequency bandwidth with high resolution. Wigner-Ville Distribution (WVD) has excellent time-frequency focusing property, but the amount of calculation and storage space are increased sharply with the higher calculation resolution demanding. A fast calculating method is proposed for selected bandwidth zoom WVD analysis. The method improves the Chirp-Z Transform (CZT) algorithms, and combines that with WVD, improves greatly calculation performance of high resolution zoom WVD analysis. Computer simulation and experimental result at sea demonstrate the validity of the presented method.