Although considerable progress has been made in the applications of active noise and vibration control since the pioneering work of 2, successful implementations of these techniques have recently been made. Such success can be attributed to the rapid progress of the technology in three major areas: 1) novel implementation of the electro-acoustic transducers, 2) development of the advanced adaptive control algorithms, and 3) inexpensive and reliable applications of the digital signal processing (DSP) hardware.
In order to compensate for the fact that majority of the models are inaccurate most active noise controllers are made adaptive. These controllers can operate with limited modeling information and their major advantage is that controllers can be changed if the system response varies. Implementations of the adaptive feedforward ANC systems are now a common practice. The feedforward algorithm uses both a reference signal, that is ideally unaffected by the controller, and an error signal,...
