SigSpec User's Manual

TL;DR

SigSpec is a comprehensive software tool for spectral analysis of time series data, capable of detecting multiple frequencies, handling irregular sampling, and analyzing multiple datasets simultaneously, with applications in various scientific fields.

Contribution

It introduces an analytical method for spectral significance, advanced prewhitening techniques, and multi-dataset analysis features, enhancing the detection of periodic signals in noisy and gapped data.

Findings

Accurately computes spectral significance levels for arbitrary sampling.

Effectively detects multiple and non-sinusoidal periodicities.

Handles multi-time series analysis with differential significance spectra.

Abstract

{\sc SigSpec} computes the spectral significance levels for the DFT amplitude spectrum of a time series at arbitrarily given sampling. It is based on the analytical solution for the Probability Density Function (PDF) of an amplitude level, including dependencies on frequency and phase and referring to white noise. Using a time series dataset as input, an iterative procedure including step-by-step prewhitening of the most significant signal components and MultiSine least-squares fitting is provided to determine a whole set of signal components, which makes the program a powerful tool for multi-frequency analysis. Instead of the step-by-step prewhitening of the most significant peaks, the program is also able to take into account several steps of the prewhitening sequence simultaneously and check for the combination associated to a minimum residual scatter. This option is designed to overcome the aliasing problem caused by periodic time gaps in the dataset. {\sc SigSpec} can detect non-sinusoidal periodicities in a dataset by simultaneously taking into account a fundamental frequency plus a set of harmonics. Time-resolved spectral significance analysis using a set of intervals of the time series is supported to investigate the development of eigenfrequencies over the observation time. Furthermore, an extension is available to perform the {\sc SigSpec} analysis for multiple time series input files at once. In this MultiFile mode, time series may be tagged as target and comparison data. Based on this selection, {\sc SigSpec} is capable of determining differential significance spectra for the target datasets with respect to coincidences in the comparison spectra. A built-in simulator to generate and superpose a variety of sinusoids and trends as well as different types of noise completes the software package at the present stage of development.