The Spectral Trend Plug-in is designed to provide power information over a selected time or page range for a specified data channel. Total power is calculated for the entire frequency range and as well as up to 10 user-definable frequency bins. The output is displayed graphically and the user can define a viewing window for paging through the output or view the entire output at once on a relative or absolute scale. In addition 3, 5, and 7 point smoothing options are available. The output can be saved in either the Grass propriety binary format for importing back into the plug-in for later viewing and/or it can be saved in ASCII file format for use with third-party analysis and publication packages.

The Spectral Trend Plug-in calculates power from FFTs performed over the user-defined interval. A variety of Windowing functions are available to minimize spectral leakage. Also, an overlap can be specified that compensates for the effects of the windowing and the short time interval.

For advanced analysis, the individual FFTs used to calculate the power information can be saved in ASCII file format. The ASCII file provides all the information needed to analyze the data further in third-party analysis or publication packages.