【作者】 刘刚；

【导师】 相敬林；

【作者基本信息】 西北工业大学 ， 机械电子工程， 2001， 硕士

【摘要】 高阶统计量是研究非因果、非最小相位系统和非高斯信号的主要分析工具。它在信号检测、谐波恢复及特征提取等方面都有着特有的优越性。本文在理论分析的基础上，结合国防预研项目，对高阶统计量在信号处理领域中，尤其是舰船辐射噪声的特性分析方面，进行了研究。 文章首先分析了舰船辐射噪声的产生机理进行了分析并介绍了高阶统计量的定义和性质，特别指出了高阶统计量对高斯过程不敏感，这是我们利用它进行信号检测和估计的理论依据。双谱由于其相对小的计算量，使其成为最常用的信号分析方法。因此，本文利用了一种基于非参数法双谱分析的谐波信号精确重构方法对舰船辐射噪声的线谱分量进行了重构；另外，对于通过Hilbert变换解出的舰船辐射噪声包络进行双谱分析，有效地提取出了舰船轴频线谱。仿真结果和实船信号分析表明：上述方法可以有效地提取谐波特征和基频分量。 同时本文也讨论了基于参数法的舰船辐射噪声线谱分量的重构，相对非参数法双谱分析，该方法可利用较少的数据量达到较高的分辨率，但对于阶数的确定非常重要。 最后，本文介绍了舰船辐射噪声连续谱分量的的重构方法，同之前重构出的线谱分量结合在一起，完整地对舰船辐射噪声进行重构。更多还原

【Abstract】 Higher-order Statistics (HOS) is the primary analysis tools which can be used to analyze noneasual system, nonminimum phase system and nongaussian signal. It possesses plenty of advantages in signal detection, harmonic retrieval and feature extraction. On the bases of theory analysis, combining whth National Defense Predictive Projects, the usage of HOS in signal processing domain, especially in features analysis based on ship-radiated noise, is explored in the paper.First, the mechanism of generation of ship-radiated noise, and then, the definition and properties of HOS are introduced. We especially notice that HOS is insensitive to Gaussian process. This is the theoretical basis for us to use it in signal detection and estimation. Bispectrum is the method widely used in signal processing for its less calculations and higher resolution. Using the method of harmonic reconstruction based on non-parameter bispectrum estimation, the line spectrum components of ship-radiated noise can be reconstructed precisely. In addition, the envelope of ship noise waveform can be remodulated utilizing Hubert transform, and the spectrum components with line rotation frequency of propeller shaft are extracted effectively by bispectrum analysis. Computer simulations and ship-radiated noise data show that the method can effectively extract harmonic features and shaft rotation frequency.In this dissertation, the harmonic reconstruction based on parameter bispectrum estimation is also discussed. Comparing with non-parameter bispectrum estimation, parameter bispectrum estimation can achieve higher resolution, less number of data are required, but it is very important to select the correct model order.At last, the reconstruction method of continuous spectrum components is introduced in this dissertation, and then the waveform reconstruction of ship-radiated noise is completed with superimposed line components of the noise.更多还原