基于VMD自适应模态重组的光学下变频信号分离方法

Optical down-conversion signal separation method based on VMD adaptive modal recombination

光学下变频技术可将宽频带内全部电磁信号同时下变频到低频区间进行接收,是一种新型宽频带电磁环境快速接收技术。但是,获取的光学下变频信号中包含源个数未知、带宽不同的多种信号,现有信号分离方法需要获知源信号的个数,且无法同时分离窄带信号和宽带信号。为实现对光学下变频信号的自动分离,提出了一种基于变分模态分解(VMD)自适应模态重组的光学下变频信号分离方法。通过频谱分割因子和频谱包络检测,对光学下变频信号的VMD过分解模态进行自动重组和信号重组模态提取,实现光学下变频信号分离。对于包含普通脉冲信号、宽带码分多址(WCDMA)信号和线性调频脉冲信号的光学下变频信号,可自动实现对三种信号的分离,且与原信号的相似系数均高于0.97。实验结果表明,所提及方法在分离光学下变频信号时无需获知源信号的个数,并能同时分离具有不同带宽的多种源信号。

Optical down-conversion technology can simultaneously down-convert all electromagnetic signals within a wide frequency band to the low-frequency range for reception,and is a new type of fast reception technology for broadband electromagnetic environments.However,the obtained optical down-conversion signal contains multiple signals with unknown number of sources and different bandwidths.Existing signal separation methods need to know the number of source signals and cannot simultaneously separate narrowband and broadband signals.To achieve automatic separation of optical down-conversion signals,a method for optical down-conversion signal separation based on VMD adaptive mode recombination is proposed.By using spectral segmentation factors and spectral envelope detection,the VMD over decomposition modes of optical down-conversion signals are automatically recombined and signal recombination modes are extracted,achieving the separation of optical down-conversion signals.For optical down-conversion signals containing ordinary pulse signals,WCDMA signals,and linear frequency modulation pulse signals,this method can automatically separate the three types of signals,and the similarity coefficients with the original signal are all higher than 0.97.The experimental results show that the method proposed in this paper does not need to know the number of source signals when separating optical down-conversion signals,and can simultaneously separate multiple source signals with different bandwidths.