Frequency domain windowing
The Energy-time Curve is computed by first transforming from time domain to frequency domain.
If 
is checked, this transform is performed faster using a Fourier transform with a data length of an order of two. The data are padded with zeros to get this length. This may introduce an error if a DC-component exists.
After the Fourier transform, a window may be applied to the complex frequency data before performing the inverse transform. The following choices are possible:
