How it works
Active noise/vibration control is the art of fighting noise (or vibration) with opposite phase noise (or vibration). When the
opposite phase noise is combined with the original noise, the result is almost silence. The problem to solve to realize
such a system is then to calculate that opposite phase noise (or vibration).
An active noise control system uses adaptive digital signal processing to reduce noise at certain places in an enclosure, or
in some cases in the whole space of interest (car cabin, airplane fuselage, room, etc). Given a clean reference of
the original noise and the sensors measurement at certain error points, the signal processor
calculates some control signals to drive the control actuators which produce the opposite phase noise/vibration at the control points.
The goal of the calculated control signals is to minimize the sound pressure level (or vibrations) at the control positions as shown
in the figure above.