我有一个数据集（数组），我需要找到周期性它。我该如何操作??请帮助。感谢很多提前。一些身体说我可以使用FFT，但我不知道如何将它给我periodicity.Your帮助AP preciated.Thanks一次。

I have a dataset (an array) and i need to find the periodicity in it. How should i proceed..??Please help. Thanks a lot in advance. Some body said i can use FFT but i am not sure how will it give me the periodicity.Your help is appreciated.Thanks once again.

推荐答案

对于这个任务，最好使用自相关。

For this task it's best to use the autocorrelation.

FFT是在错误工具用于查找的周期。

The FFT is the wrong tool to use for finding the periodicity.

考虑，例如，在你的波形是通过相加两个简单的正弦波，一个具有周期为2秒（0.5赫兹）制成的情况下，和其他与3秒（0.333赫兹）。该波形将具有6秒（即，2 * 3），但是傅立叶频谱将只显示两个峰在0.5赫兹，和0.333赫兹。

Consider, for example, a case where your waveform is made by adding together two simple sine waves, one with a period of 2 seconds (0.5 Hz), and the other with 3 seconds (0.333 Hz). This waveform will have a periodicity of 6 seconds (i.e., 2*3), but the Fourier spectrum will only show two peaks at .5 Hz, and .333 Hz.