The Fourier folder


The Fourier tab does basically consist of two parts:

The Fourier calculation settings panel:


Title Defines the name of the Fourier spectrum.
From Defines the lower bound of the frequency range to be calculated.
To Defines the upper bound of the frequency range.
Step rate Defines the accuracy of the frequency grid for the Fourier calculation. Three default options for the step rate quality are available and can be selected by the combo box: High, Medium and Low. In order to set a user defined value select Custom and type the value into the text field next to the step rate combobox. Please note: The smaller the step rate the longer the calculation will take.
Nyquist Displays the Nyquist frequency for the current selection of time points. This value should be a good estimate for the upper limiting frequency due to the sampling pattern in the time string that is currently selected. The algorithm estimates the average time gap between neighboring points while ignoring large gaps.
Use weights Displays a string that indicates which weights are being used for the Fourier calculation. If no weights are used "none" will be displayed.
1 use the weights assigned to the substrings of attribute #1
2use the weights assigned to the substrings of attribute #2
3use the weights assigned to the substrings of attribute #3
4use the weights assigned to the substrings of attribute #4
puse point weight
duse deviation weight
Edit weight settings Opens the weight-selection dialog.
Calculations based on Defines the type of data to be used for the calculation. Original data, Adjusted data, Residuals at original, Residuals at adjusted. If Spectral window is chosen the program will calculate the spectral window which is centered at zero frequency and reflects the pattern caused by the structure of gaps in the time string.
Compact mode The output of the Fourier calculation can be quite extensive. To reduce the output Peaks only can be selected. In this case only local maxima and minima are saved. If All is selected, all data points of the spectrum are stored.
To start the calculation based on the settings in the Fourier folder either press the button Calculate or type the shortcut Alt+C.

The Fourier list


All calculated Fourier spectra are stored in the Fourier list box. Every list entry consists of the title of the spectrum and - in parentheses - the frequency and amplitude of the highest peak. By clicking on a spectrum the settings for that calculation will be loaded and displayed.

The buttons below the list provide the following functions:
Rename spectrum Change the title of the highlighted Fourier spectrum.
Export spectrum Save the data points of the highlighted Fourier spectrum into a file. In order to export a set of spectra the Data Manager should be used.
Delete spectrum Erase the highlighted Fourier spectrum.
Display table Show the table of the data points for the highlighted Fourier spectrum
Display graph Show the highlighted Fourier spectrum as a plot on the monitor.
Please note:
The functions of these buttons are also accessible by a pop-up menu.

The log folder