为了定量分析不同状态下电磁环境的变化,并有效提取电磁环境变化的干扰特征,提出了基于小波包分解和样本熵的电磁干扰分析方法.首先,时电磁环境的样本信号进行小波包分解,然后分别计算分解后备频带信号的能量谱系数和样本熵,通过能量谱系数和样本熵这两个指标的对比,综合判断电磁环境是否发生变化.仿真分析表明:样本熵可以弥补能量谱系数无法区分频率间较小的频率成分这一缺点.最后,通过某电子设备不同工作状态下电磁环境的实验分析,验证了该方法的可行性和有效性.%To analyze the change of electromagnetic environment in different states quantitatively and extract its interference feature information effectively, an analytical method of electromagnetic interference is proposed based on the wavelet packet decomposition and sample entropy (SampEn). Firstly, the sample signals of electromagnetic environment were decomposed by wavelet packet. Then, the energy spectrum coefficient and SampEn of signals at each frequency band were computed. The two indexes in different working states were compared comprehensively to judge whether the electromagnetic environment was changed or not. The simulation shows that SampEn reflects the complexity of the sample signal's frequency, which can make up the shortcoming of the energy spectrum coefficient that cannot distinguish the frequencies of frequency-closed signal. Finally, the experiment of electromagnetic environments in different working states by certain electronic equipment validated the feasibility and effectiveness of the proposed analytical method.
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