【作者】 陈文武；

【导师】 黎洪生；

【作者基本信息】 武汉理工大学 ， 通信与信息系统， 2003， 硕士

【摘要】 本文主要研究了基于DSP的EMD方法实现技术。 传统非平稳信号处理方法存在不足和缺陷。短时傅立叶变换依赖于传统的傅立叶谱分析，所以限制于假定待分析数据是分段平稳的这个条件。Wigner-Ville分布克服了短时傅立叶分析的部分缺点，具有较高的分辨率，但存在严重的交叉干扰项。目前处理非平稳信号最好方法之一的小波分析也存在一些缺点。经验模态分解方法(EMD方法)是近年来出现的一种分析非线性、非平稳信号的新方法。使用这种方法可以将复杂的数据信号分解为有限数量的本征模函数(IMF)，对IMF分量进行Hilbert变换可以获得信号的时频分布。Huang提出的这个方法是通过Hilbert-Huang变换(HHT)工具包实现的。 鉴于目前国内外对EMD方法的研究多限于软件方面，课题尝试结合DSP和PCI技术来实现EMD方法，其优点和意义如下： 1)采用硬件系统来实现EMD方法可以方便地实现现场在线数据采集和分析，这在一些要求实时处理或准实时处理的场合尤为重要； 2)利用DSP强大的信号处理能力来实现EMD方法，可以充分发挥其高速和高效的优点： 3)可以充分利用PCI总线高传输速度、大地址空间等优点。 针对EMD方法的实现过程及DSP和PCI的特点，本文探讨了研制采集处理卡实现EMD方法的技术问题。论文所完成的工作如下： 1．实现了板卡的PCI总线接口，利用PCI总线将数据直接传到系统内存，有效解决数据的实时传输和存储，为信号的实时处理提供方便。 2．实现了输入信号的高速同步采集。所采集数据存放在DSP的片内RAM。 3．运用DSP实现采集数据的EMD分解。利用一种简易的镜像延拓处理信号的边缘效应，将存入片内RAM中的数据进行EMD分解，将每次分解所得的IMF分量传至PC机。 4．PC机端应用程序实现IMF分量的存储和显示工作。 本文作为一个有益的尝试，为EMD方法硬件实现的进一步探索和研究积累了一些经验。更多还原

【Abstract】 The implementation technology of HMD method based on DSP is researched in this paper.Traditional non-stationary data processing methods have some disadvantages. Short-time Fourier transform relies on the traditional Fourier spectral analysis, so it is limited to the assumption of the data to be piecewise stationary. The shortcoming of Wigner-Ville is the severe cross terms as indicated by the existence of negative power for some frequency ranges. So far one of the best available methods to process non-stationary data is wavelet analysis. However it has many problems. Empirical Mode Decomposition method (EMD) is a new method for analysing nonlinear and non-stationary data, with which any complicated data set can be decomposed into a finite and often small number of Intrinsic Mode Functions (IMF) that admit well-behaved Hilbert transforms. Thus the energy-frequency-time distribution of the signal is constructed. This method developed by Huang et al is implemented through HHT (Hilbert-Huang Transform) toolbox.Because domestic and oversea research on EMD method at present is mainly focused on software, implementation of EMD method based on DSP and PCI is discussed in the paper. It has following advantages:1) It’s convenient to sample and analyze on-line signal through implementing EMD method by hardware, especially in some situations requiring realtime processing and quasi-realtime processing;2) It’s easy to show DSP’s high-speed and high-efficiency as using its powerful signal processing ability to implement EMD method;3) Rapid data transmission and other high performance of PCI local bus can be fully used.According to the realizing procedure of EMD method and features of DSP and PCI, technologies of developing a signal acquisition/processing card and implementing EMD method is discussed. The paper has fulfill following jobs:1. Implementation of PCI interface of this card. Data is transmitted to system memory directly with PCI local bus, which solves the realtime transmission and storage of data and also provides convenience for signal realtime processing.2. Implementation of data acquisition with high speed and synchronization. The data is stored in on-chip RAM of DSP.3. EMD method is implemented by DSP. A simple mirror-extension method is taken to sovle the end extending issue in EMD method. And data in on-chip RAM is processed by the approach, and each IMF is transmitted to PC.4. The application on PC serves as the implementation of storage and display of IMF results.The paper provides some experiences for future research on EMD implementation by hardware.更多还原