|dc.description.abstract||In this dissertation, the enhanced digital filter designing techniques for the applications of active noise control are proposed. These techniques include two approaches; phase compensated scheme and fuzzy adaptive scheme. One can utilize the proposed schemes on the conventional digital filter designing techniques to enhance the performances of active noise cancellation. The main merit of these approaches is to overcome the nonlinear distortion effect, which arise from the analog devices and quantization, and then help to improve the ability of noise reduction.
Secondly, the proposed method can save the computing complexity in realizing an active noise control system. Traditionally, one has to identify the system dynamics of the noise control system including circular duct, speaker, microphone and peripheral electronic device in advance to design a noise controller. This dissertation proposes the fuzzy adaptive algorithm, which can self-tune the free parameters in the active controller during the noise control process. Hence, there is not any plant information that needs to be identified. Besides, the proposed approach can process both the numerical and linguistic information, which helps to design an active noise control system easily.
Several experiments and simulations are used to demonstrate the proposed approaches in an acoustic duct. It is proved that using enhanced digital filter techniques, the noise reduction abilities of broadband noises as well as narrowband noises are improved. Besides, the designing procedure of active noise control system is also simplified.||en_US|