Either ring or amplitude modulate a carrier signal with a modulator signal. The modulation type is selectable via the switch. The modulation amount itself can be modulated for more exciting sonic textures. Finally, the output gain is adjustable.
In the sound demo you can first hear the unaffected bass line. At bar 5 it gets amplitude modulated by a 4 octave higher sine wave. At bar 9 it is ring modulated by that same sine wave and the amount is modulated by a 2 Hz sine wave.