4.7.3 Spectral Analysis

This function conducts spectral analysis with user-defined parameters.

Steps:

1. Select a data file in the Acycle Main Window

2. Select Timeseries --> Spectral Analysis menu

3. Select one method for spectral analysis.

Options are

• Multi-taper method (MTM) (Thomson, 1982),

• Lomb-Scargle spectrum (Lomb, 1976; Scargle, 1982), and

• MatLab’s periodogram.

4. If Multi-taper method (MTM) is selected, then the Method panel may be changed.

The default value is using 2π MTM, with a no zero-padding.

5. Plot panel: set the max frequency in the coming figure.

6. Red Noise panel

AR(1) noise model using RedNoise.m by Husson (2014) and modified by Linda Hinnov (GMU).

Robust AR(1) noise model follows Mann and Lees (1996).

7. Run or Run & Save button, generates power spectrum (and save power spectrum data and AR(1) series)

Shortcut keys

• [Mac]: ⌘ + S

• [Windows]: Ctrl + S

2π MTM power spectrum of the Wayao Carnian gamma-ray data (interpolation = 0.33; detrend 80-m lowess trend)

New file name: *-2piMTM-CL.txt, means 2π MTM and confidence level series.