The Astrophysical Journal · 1986 · 1.4K citations · 0 references
The calculation of the modified periodogram for unevenly sampled data and the proper definition of the variance used to normalize its power are reviewed. The study presents a technique for detecting the presence and significance of a period in unevenly sampled time series, discusses the crucial choice of independent frequencies, and prescribes a method for detecting alias frequencies. The authors derive an empirical formula for estimating the number of independent frequencies, review the formula for frequency uncertainty, and investigate the signal‑to‑noise ratio and point requirements for extracting one or two periodicities. The authors prove that the probability of a periodogram peak being noise or signal can be assessed only when the total variance normalizes the power, and they demonstrate the minimum number of points needed to reliably measure a signal. Published in The Astrophysical Journal, March 1986, DOI: 10.1086/164037.
view Abstract Citations (1372) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Prescription for Period Analysis of Unevenly Sampled Time Series Horne, J. H. ; Baliunas, S. L. Abstract A technique is presented for detecting the presence and significance of a period in unequally sampled time series data. The calculation of the modified periodogram for unevenly sampled data is reviewed. The proper definition of the variance that is used to normalize the power of the modified periodogram is clarified. It is proven that the probability that a peak in the periodogram is noise or signal can be easily assessed by the method given here only when the total variance of the data is used to normalize the periodogram power. The crucial choice of independent frequencies in calculating both the periodogram and the false alarm probability from unevenly sampled data is discussed. An empirical formula for estimating the number of independent frequencies is derived. In addition, the formula for the uncertainty of a frequency identified in the periodogram is reviewed. A method for detecting the presence of an alias frequency caused by the interaction of the window and signal is prescribed. With some examples of periodic signals, the minimum number of points required to measure reliably a signal are shown. The signal-to-noise ratio and the number of points required to extract signals when one or two periodicities are present in the time series are investigated. Publication: The Astrophysical Journal Pub Date: March 1986 DOI: 10.1086/164037 Bibcode: 1986ApJ...302..757H Keywords: Computational Astrophysics; Periodic Functions; Time Series Analysis; Fourier Analysis; Probability Distribution Functions; Sampling; Signal To Noise Ratios; Variance (Statistics); NUMERICAL ANALYSIS; NUMERICAL METHODS full text sources ADS |