Abstract: The traditional DEMON(Dectecion of Envelope Modulation on Noise) method is difficult to obtain the modulation characteristics when the signal modulation frequency or modulation depth changes with time. For non-stationary modulation characteristics, using Hilbert-Huang Transform (HHT) data adaptive features and high-resolution time-frequency analysis capabilities as well as mathematical morphology filter (MMF) on the signal noise reduction performance, a modified method “MH_DEMON” based on HHT and MMF is given. Simulation data and real acoustic radiated noise experimental data analysis shows that, MH_DEMON can extract non-stationary broadband amplitude modulation characteristics, which could suport both modulation source for the target classification and motion analysis.