【摘要】 提出了用比例、旋转、径向位移表示的三参数Chirp时频原子和基于分数阶傅里叶变换的最佳原子搜索方法,该方法利用分数阶傅里叶变换先估计Chirp原子的最佳旋转参数,并先保持比例参数不变,仅调整径向移位一个参数来搜索最佳Chirp原子。仿真实验结果表明,提出的搜索方法能从整体上把握信号的最大时频结构,提供信号的稀疏表示,避免了原始的匹配追逐算法固有的局部优化所造成的对信号的过分解。更多还原

【Abstract】 The three-parameter Chirp atoms expressed by scale,rotation and radial-shift and an improved method based on the fractional Fourier transform for searching the best one are proposed.This method firstly estimates linear Chirp rate of the atom by applying fractional Fourier transform and then radially shifts the atom along estimated orientation to regulate the time center and frequency one so that the best Chirp atoms are obtained.Simulation results show that the proposed method can provide signal sparse representation and most time-frequency information existed in the signal and can also avoid inherence greed decomposition of original MP thanking to beforehand estimating and grasping most time-frequency structure.更多还原