Empirical Mode Decomposition Theory Of Ship Radiated Noise Line Spectrum Analysis

Line spectra provide significant information of ship-radiated noise.Extracting Linear spectrum from ship-radiated noise is a key technique in identification of underwater targets. This paper focus on Linear spectrum of ship-radiated noise signal based on empirical mode decomposition.1.First, the method of wavelet analysis is introduced. Multiresolution analysis thoey and denoising algorithm based on wavelet analysis are discussed. Secondly, a new method of signal analysis-empirical mode decomposition (EMD) is introducted in this paper.The characteristic of EMD adaptive filter is discussed in detail.Thirdly Hilbert HuangTransformspectrum and marginal spectrum is introduced.2. Because the length of wavelet is limit, it is difficult for wavelet analysis to time-frequency analysis. Compared with traditional wavelet transform analysis EMD is a better method for processing signal. The multiresolution analysis of wavelets combines the advantages of panorama and detail annalysis of signal. But EMD which is a method of real adaptive analysis needn't give wavlet in advance. This point is different from wavelet transform. So EMD is a effective method for analysis of signals.3.Mathematical model of ship radiated noise is introduced. The traditional method of linear spectrum, such as the periodographic method,autocorrelation and Burg, are dicussed. But the variance of periodographic method and autocorrelation are large, the mothod of Burg can produce false peak. So in this paper, a united method of Linear spectrum analysis of ship radiated noise simulation signal based on empirical mode decomposition is proposed. Compared with traditional Linear Spectrum analysis, it is a better method for signal analysis and processing.4. In this paper, a new method of linear spectrum analysis of ship radiated noise simulation signal based on ensemble empirical mode decomposition (EEMD) is disscussed. Linear spectrum of ship radiated noise simulated signals are extracted based on EEMD. Compared with traditional wavelet transform analysis, EEMD is a better method for signal analysis and processing. 5. In this paper a new method of adaptive filter signal analysis-EMD-LMS is introduced. The ship-radiated noise signals are analyzed by using the proposed method. Compared with traditional spectrum analysis and wavelet analysis, EMD-LMS is a better method for signal analysis and processing. The results show that the method is effective in extracting spectral lines from ship-radiated noise.