The FFT Graph Options dialog allows you to control how your data are plotted.
Add and change the title text and its color as well as remove the title completely. The title will be placed at the top of the graph. Include symbols (including subscripts and superscripts) in the title using the drop-down menu.
Check Legend to display a legend including the names and colors of the data columns plotted on the graph.
If Peak Frequency is checked, the legend will show the frequency component with the largest amplitude.
The FFT Settings affect the way the FFT is calculated.
The Remove Linear Trend option ignores any linearly-changing offset in the data. Such an offset could appear as a spurious low-frequency component in the FFT.
The Use Window option applies a Hanning window to the data before the FFT is performed. Windowing is a technique used to minimize edge effects that result in spectral broadening in the FFT.
Set the Major and Minor Tick Style line and color.
Select the column you want to use as the Base Column. In most cases, only timed data will be used and will be the first column of the data set.
Select which columns will be analyzed and plotted.
Use these options to change the label or axis scaling for the Frequency-Axis and/or the Amplitude-Axis. It is also possible to change the scales on the graph itself by clicking and editing the values at the ends of the axes. You can also use the Autoscale graph.
Check Log Axis to plot the log of the values of the column. Each major tick of the y-axis is a power of 10.
Check Restrict Range to eliminate some data from the FFT calculation. You might have a sound waveform that has a central portion for which you want the FFT, but not the earlier or later portions. If you highlight a portion of the graph prior to setting up the FFT, the endpoint values of the selected region will be located here. Change the values to include a different data range or uncheck Restrict Range to include all data in the calculation.