这是一个使用EMD分解出IMF的例子，一个试验信号由一个tone信号，一个chirp信号，叠加得到，目的是使用EMD将这两个信号分离，得到的预期结果应该是chirp信号在高阶，tone信号在低阶，（原因是chirp信号在各个局部的频率都比tone信号高）。(This is an example of using EMD to decompose the IMF. A test signal consists of a tone signal and a chirp signal. The purpose is to separate the two signals using EMD. The expected result should be that the chirp signal is at a higher order, the tone The signal is in the low order, (because the chirp signal is higher in all local frequencies than the tone signal).)