摘要
为了改善S变换的冗余度,提高S变换的计算能力,研究了S变换的一种有效表示.通过引进一组正交基函数来局部化频谱,并保留S变换相位特性上的优势.这些正交基函数的相位特性和傅里叶频谱的相位保持直接的关系,能够紧凑频率并在时域局部化.因此可以用局部交叉谱来衡量两个时间序列中多种成分之间的相移,作为时间和频率的函数.此外,还可以定义一个广义的瞬时频率(IF)适用于宽带非平稳信号.通过基本函数和复小波的直接比较,突显了这种方法的优势.
In order to improve the redundancy and computing capability of S transform, a more efficient representation is introduced, by introducing an orthogonal set of basis functions that localizes the spectrum and retains the advantageous phase properties of the S-transform. These basis functions are defined to have phase characteristics that are directly related to the phase of the Fourier transform spectrum, and are both compact in frequency and localized in time. Therefore it can perform localized cross spectral analysis to measure phase shifts between each of multiple components of two time series as a function of both time and frequency. In addition, if can be defined that a generalized instantaneous frequency （IF）applicable to broadband nonstationary signals. A direct comparison between these basis functions and complex wavelets is performed, highlighting the advantages of this approach.
出处
《河南师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2009年第2期60-63,共4页
Journal of Henan Normal University(Natural Science Edition)
基金
国家自然科学基金(60873104)
关键词
S变换
时频分析
小波
S transform
time frequency analysis
wavelet
