水下目标辐射噪声的子波变换和双谱联合分析

首次将子波变换和双谱联合分析应用于对水下目标辐射噪声的特征提取，首先利用子波变换提取辐射噪声的动态调制分量，然后应用归一化双相干系统分析该动态调制的谐波特性，结果表明，该方法可以有效地实现动态调制分量与其他信号的分离，准确提取谐波特性，并具有很强的抗噪性。

Joint Analysis of Radiated Noise from UnderwaterVehicles Based on Wavelets and Bispectrum

It is very important to analyze the dynamic modulation components in radiated noise of underwater vehicle, which can be used to calculate the velocity of vehicle and classify the type of underwater vehicle. Traditional method is the method of detection of envelope modulation on noise (DEMON), which is to extract the dynamic modulation signal of radiated noise based on Hilbert transform first and then to estimate the fundamental frequency and harmonics. It has the disadvantages of less robustness, low accuracy and susceptibity to noise. The new method proposed in this paper is to extract the dynamic modulation components by utilizing the wavelets and then to estimate the fundamental frequency and harmonic components by using normalized bicoherent coefficients. Experimental results show that the new method can be used not only to verify the non Gaussian property, but also to extract accurately the harmonic characteristics by efficiently separating the dynamic modulation components from other signals. It also possesses the anti noise property.