中文摘要：

当信号中两个单频分量的频率在二倍频内时,经验模式分解（EMD）无法将两分量分解开。为了提高EMD的频率分辨率,根据频率外差EMD方法提出了一种改进算法。此方法增大了信号中组成分量的频率差距,使之达到EMD可分的程度,但不会使高低频率翻转。间隙非线性系统输出分析和转子复合故障诊断的应用表明,该算法能有效提高EMD的频率分辨率,分解精度高,操作简单。

英文摘要：

Two individual components in a signal with frequencies within an octave usually can＇t be decomposed by normal empirical mode decomposition（EMD） method.In order to improve the frequency resolution,an improved method based on frequency heterodyne EMD was presented.The proposed method enlarged the frequency difference of components to reach the identifying level of EMD.Moreover,the frequencies of components can＇t be turnover with the frequency heterodyne EMD method.The applications in backlash nonlinearity system analysis and rotor complex fault diagnosis showed that the proposed method could improve the resolution of EMD with high accuracy and proved to be feasible.