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In this paper,we discussed the underwater sound reverberation of moving medium,which is anon-stationary stochastic process even after compensating its energy attenuation.Evolutionaryspectra is introduced,and the non-stationary properties are described by a non-stationary factor anda characteristic width.We assumed that the Doppler shift is a stationary normal process or a normaladditive process and obtained the evolutionary spectra.After compensating the energy attenuation,a non-stationary sound reverberation can be expressed as a product of a deterministic time functionand a stationary stochastic function.The bi-hump in power spectrum is due to the non-stationarityand the non-homogeneity of the medium motion.When we use the estimation ν.i.e.the meanDoppler shift of a stationary process to estimate the mean Doppler shift of a non-stationary rever-beration process,the estimation ν is a biased one.
In this paper, we discussed the underwater sound reverberation of moving medium, which is anon-stationary stochastic process even after compensating its energy attenuation. Evolutionaryspectra is introduced, and the non-stationary properties are described by a non-stationary factor anda characteristic width. We assumed that the Doppler shift is a stationary normal process or a normaladditive process and obtained the evolutionary spectra. After compensating the energy attenuation, a non-stationary sound reverberation can be expressed as a product of a deterministic time function and a stationary stochastic function. bi-hump in power spectrum is due to the non-stationarity and the non-homogeneity of the medium motion. Who we use the estimation ν .iethe mean Doppler shift of a stationary process to estimate the mean Doppler shift of a non-stationary rever- beration process, the estimation ν is a biased one.