The common method of estimating instantaneous frequency, Hilbert transform would produce negative frequency and boundary effect. Normalized Hilbert transform had overcame the negative frequency of Hilbert transform, but the boundary effect still exist. In order to avoid using the Hilbert transform, based on the empirical amplitude-modulation frequency-modulation (AM-FM)decomposition, a new method of calculating instantaneous frequency, namely the empirical envelope method(EE) is proposed. The nature of empirical envelope method is as follows.Getting the FM signal firstly by using the empirical AM-FM decomposition, making the derivation of the FM signal, and then using the empirical AM-FM decomposition again to extract the envelope signal of derivation of the FM signal. In the paper, the detailed process of the empirical AM-FM decomposition and specific steps of empirical envelope method are given; Finally the EE method is compared with Hilbert transform method, normalized Hilbert transform method and Arccosine method by analyzing the simulation signals. The analysis results show that empirical envelope method is superior to the other method.
ZHENG Jin-de CHENG Jun-sheng YANG- Yu .
A new instantaneous frequency estimation approach—empirical envelope method[J]. Journal of Vibration and Shock, 2012, 31(17): 86-90
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