Research On The Application Of Hilbert-Huang Transformation To Vector Signal Processing

The Hilbert-Huang transform (HHT) is a new theory, which is first developed by Huang et al at the end of last century, for the signal analysis. The method decomposes signal into finite intrinsic mode functions (IMF) by the method of empirical sifting method (EMD), and then, with the Hilbert transform, the meaning instantaneous frequencies of every IMF is obtained which give precise description of the varying frequency. The HHT adaptively takes advantage of the local information of a signal at a certain time to obtain the instantaneous Information of the signal at that time.A vector sensor is an acoustic transducer composed of homocentric acoustic pressure sensors and particle velocity sensors that measure simultaneously scalar quantity (pressure) and vector quantity (pressure gradient, particle velocity, acceleration, displacement, etc) at the same location. Compared with traditional pressure sensors, vector sensors can measure acoustic information more comprehensively. More information brings wider processing space and injects more life to acoustic signal processing and sonar technology.Based on the development and actuality of HHT and vector signal processing, the thesis developed the Vector HHT theory combining them. Taking advantage of the instantaneous Information of the signal that is obtained by HHT and Vector signal processing, the instantaneous azimuth is provided and then develop Vector HHT theory, including intrinsic mode functions (IMF), empirical sifting method (EMD), Hilbert spectrum, Hilbert marginal spectrum, Hilbert azimuth spectrum, Hilbert azimuth marginal spectrum, etc. The paper detail discuss the characteristics of Vector HHT, including the multi- dimension express of Vector HHT, the azimuth estimation and electric rotation, gain, the resolving of frequency and the resolving of azimuth, etc. According to underwater acoustic signal processing, especially vector signal processing, discuss the problems in the calculation of Vector HHT: curve-fitting, end disposal, ending condition, the...