This method calculates the power spectrum of unequally-spaced data using a so called ‘date compensated’ discrete Fourier transform. This transform is defined so as to include the uneven spacing of the dates of observation and weighting of the corresponding data. The method is useful when the signal-to-noise ratio of the data is low, and for low frequency data. 

Peranso implements the algorithm a described by Ferraz-Mello1.

The DCDFT dialog box is similar to the Lomb-Scargle dialog box. Prominent periods of the Period Window appear as peaks.


(1) Ferraz-Mello, S., 1981, Astron. J., 86(4)