说明：  VMD是通过迭代搜寻变分模型（具体怎么搜寻，请亲们自己看，我主要讲他的大概）最优解， 来确定我们所知的模态uk(t)及其对应的中心频率ωk和带宽。 每个模态都是具有中心频率的有限带宽（就是在频域中有在一定的宽度）。所有模态之和为源信号。
(VMD is to determine the modal UK (t) and its corresponding central frequency, k and bandwidth by iteratively searching for the optimal solution of the variational model (see dear friends for details, and I will mainly talk about his approximate solution). Each mode is a finite bandwidth with a central frequency (that is, a certain width in the frequency domain).The sum of all modes is the source signal.)