Periodogram analysis of unequally spaced time-series, as part of many biological rhythm investigations, is complicated. The mathematical framework is scattered over the literature, and the interpretation of results is often debatable. In this paper, we show that the Lomb-Scargle method is the appropriate tool for periodogram analysis of unequally spaced data. A unique procedure of multiple period searching is derived, facilitating the assessment of the various rhythms that may be present in a time-series. All relevant mathematical and statistical aspects are considered in detail, and much attention is given to the correct interpretation of results. The use of the procedure is illustrated by examples, and problems that may be encountered are discussed. It is argued that, when following the procedure of multiple period searching, we can even benefit from the unequal spacing of a time-series in biological rhythm research.

中文翻译：

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用Lomb?Scargle方法在不等距时间序列中多周期搜索的过程

作为许多生物节律研究的一部分，不等距时间序列的周期图分析很复杂。数学框架散布在文献中，对结果的解释常常是有争议的。在本文中，我们表明 Lomb-Scargle 方法是对不等距数据进行周期图分析的合适工具。衍生出一种独特的多周期搜索程序，有助于评估时间序列中可能存在的各种节律。详细考虑了所有相关的数学和统计方面，并非常注意对结果的正确解释。通过示例说明了该过程的使用，并讨论了可能遇到的问题。有人认为，当遵循多期搜索的过程时，