说明：  变分模态分解，VMD（Variational mode decomposition）是一种新型的基于频域的完全非递归信号分解估计方法，它结合了经典的维纳滤波，Hilbert变换与频率混合。
(Variational mode decomposition (VMD) is a new non recursive signal decomposition and estimation method based on frequency domain. It combines the classical Wiener filter, Hilbert transform and frequency mixing.)