基于FrFT和三次样条插值的瞬时频率估计方法

Instantaneous frequency estimating method based on FrFT and cubic spline interpolation

瞬时频率估计作为非平稳信号分析的主要内容,具有重要的研究意义。针对基于微元法和分数阶傅里叶变换的瞬时频率估计方法在实时性、抗噪性等方面的不足,改用黄金法快速搜索最佳分数阶比以增强其实时性,引入三次样条函数对分段信号中间点频率进行插值以提高其抗噪性。仿真结果表明,本文方法时耗约为现有方法的1/3,在不同信噪比下,本文方法的RMSE和MAE都约为现有方法的1/2,是一种有效的瞬时频率估计方法。

As an main part of nonstationary signal analyse,instantaneous frequency estimation is worth while to in-vestigate.For the real time performance and the noise immunity of the method based on element analytic and FrFT still can not satisfy the desire,an instantaneous frequency estimating method based on FrFT and cubic spline interpolation is proposed.The real time performance is enhanced by adopting golden law to search the optimal order of the FrFT.The noise immunity is improved by the cubic spline interpolation between the middle-time points＇ frequencies of sub-signals.Simu-lation results demonstrate the validity of the proposed method and show that the proposed method＇s time cost is about 1/3 of the present method,the RMSE and MAE of the proposed method are both about 1/2 of the present one.