4.7.6 Filtering

This function generates a filter output series based on the selected data file with user-defined parameters.

Data requirement

• The data file must be an evenly spaced depth/time series.

• The dataset should be a "zero-mean" series.

  • If not, you will need to remove the mean value of the data series using "TimeSeries" -> "Detrending" tool.

  • In the "Acycle: Detrending" GUI, select the "Mean" checkbox and click "OK" button.

  • And select the "Mean" at the bottom of the "Detrending" GUI.

  • You will have two new files including one demeaned data, which should be used in the filtering process.

Steps:

1. Select a data file in the Main Window.

2. Select Timeseries --> Filtering menu

3. Bandpass filter panel

very important!

Type min and center frequencies of the passband, the max frequency will be set automatically.

The bandpass filters are MatLab’s Butter, Cheby1, and Ellip filters and Gaussian, and Taner-Hilbert filters.

The recommended filters are Gaussian filter and Taner-Hilbert filters code by Linda Hinnov (Kodama and Hinnov, 2015).

Tips: The Taner-Hilbert filter generates both filtered output series and the amplitude modulation of the filtered output series.

Click Save Data button to save filtered data.

4. Highpass and lowpass panel

Two options are MatLab’s Butter and Ellip filter. Type cutoff frequency in the text box and select a filter.

Click Save Data button, the filter outputs will be displayed.

5. Power spectrum plot

give options for display the power spectrum in the right of the GUI.

Shortcut keys

[Mac]: ⌘ + F

[Windows]: Ctrl + F

New file name: *-gaus-0.0243+-0.0053.csv, means filtered output series using Gauss filter and a 0.0243 ± 0.0053 cycles/unit bandpass.

*-Tan-0.03+-0007.csv and *-Tan-0.03+-0007-AM.csv, mean filtered output series using Taner-Hilbert filter and a 0.03 ± 0.007 cycles/unit bandpass, with its amplitude modulation file saved.

Original La2004 solutions and filtered 41 kyr cycles