基于改进经验AM-FM解调的复杂信号瞬时特征分析方法

摘要

分析了Hilbert变换在计算复杂单分量信号瞬时特征时存在的不足,研究了一种称为经验AM-FM解调的信号瞬时特征计算方法,并对算法进行了改进.针对其在计算瞬时频率时易受噪声影响的不足,提出将该算法与加权平滑相位差分法相结合来抑制噪声的影响.结合经验模式分解和改进的经验AM-FM解调算法,提出了一种适合复杂多分量信号解调分析和瞬时特征计算的方法.数值仿真和实验数据验证了该改进方法的有效性.%Same limitations of the Hilbert transfonn (HT) for computing imtantaneous characteristics of complicated monocomponent signals were analyzed.As an enhancementofthe HT，an algorithm named empincal AM-FM(amplitude and frequency modulation) demodulstion was investigated and then improved. Firstly,the weighted smoothing phase-difference method was applied to this demodulation algorithm to increase the precision of instantaneous frequency for naisy signals. Secondly,by combining the Empirical Motle Decomposition (EMD) and the improved empirical AM-FM demodulation algonthm,a method suitable for instantaneous characteristics extractiand complicated multi-component signals was proposed. The validity of the improvements was confirmed by numerical simulations and expenmental signals.