中文摘要：

瞬时频率计算是关系到经验模式分解实用性的关键,但是传统瞬时频率的计算方法对于信号分析的准确性有很大的影响。尽管非平稳信号的频率变化率可以用有限次的多项式表示,而最大似然估计、最小二乘法等相位建模估计方法计算量大,因此对于内蕴模式分量计算得到的瞬时频率仍然存在一些问题,其中边界效应更为明显。提出采用高阶模糊度函数来进行相位参数估计的方法,对内蕴模式分量的瞬时频率进行计算,在此基础上构建Hilbert时频谱进行信号分析。应用高阶模糊度进行瞬时频率计算,可以减小计算量,提高瞬时频率估计的准确性。采用仿真和实际信号验证方法的有效性,研究表明此方法可以有效消除边界效应影响,提高Hilbert时频谱的可靠性。

英文摘要：

Instantaneous frequency（IF） calculation is a key step for empirical mode decomposition（EMD）.But signal analysis accuracy is not very well for practical condition signal analysis based on traditional IF calculation method.Although non-stationary signals can be modeled as polynomial phase signals（PPS）,traditional phase model estimation methods are not very suitable for practical application,such as maximum likelihood estimation and the least squares method.In most circumstances,a lot of calculations are needed.Thus,several problems need to be solved during IF calculation for intrinsic mode function obtained from EMD.The boundary effect for signal analysis is very obvious.High-order ambiguity function（HAF） is put forward for IF calculation.Then,Hilbert time-frequency spectrum can be constructed for signal analysis.HAF can reduce computation and improve IF estimation accuracy.Simulation signal and practical monitored signal are used to testify the effectiveness of this method for IF calculation.The research shows that this method can effectively eliminate the influence of boundary effect and improve the reliability of Hilbert time-frequency spectrum.