The Exciter generates high frequency components that are not part of the original signal. It does this by employing a nonlinear distortion process that resembles overdrive and distortion effects.
Unlike these effects, however, the Exciter passes the input signal through a highpass filter before feeding it into the harmonics (distortion) generator. This results in artificial harmonics being added to the original signal. These added harmonics contain frequencies at least one octave above the threshold of the highpass filter. The distorted signal is then mixed with the original, dry signal.
You can use the Exciter to add life to recordings. It is especially well suited to audio tracks with a weak treble frequency range. The Exciter is also useful as a general tool for enhancing guitar tracks.
Note: In most cases, higher Frequency and Harmonics values are preferable, because human ears cannot easily distinguish between the artificial and original high frequencies.