本篇論文針對窄頻噪音使用改良式直接/平行組態之主動噪音控制器進行噪音消除。傳統直接/平行組態之主動噪音控制器,使用單一誤差訊號做適應性濾波器的權重調整,而我們提出一個方法,利用無相位延遲的帶通濾波器將誤差訊號頻率分離,在多組適應性濾波器中,誤差訊號與輸入訊號的數目相同且頻率相對應,結合直接/平行組態控制器做適應性濾波器的權重調整。新的方法提高直接/平行組態控制器的性能,並且在理論推導中顯示,改良式直接/平行組態比傳統的方法有較快的收斂速度,最後以MATLAB模擬分析的方式,利用不同噪音訊號比較改良式與傳統的控制器,在穩態與暫態中的表現,結果分析顯示,改良式消噪效果比傳統來的好,且在收斂時間也比傳統來的快。
This thesis proposed a new direct/parallel form narrowband active noise control (ANC) system. The conventional direct/parallel form uses a single error signal to update all the adaptive filters. Therefore we use a delayless filter to separate the frequency components of the error signal based on the sinusoidal frequencies of input signals to update the corresponding adaptive filters in the direct/parallel controller. In the adaptive algorithm derivation prove that we improve the performance of noise reduction and convergence speed for this new direct/parallel narrowband ANC system. Theoretical analysis is performed to demonstrate the increased convergence speed. We use many different narrowband noises in computer simulation, and the results are conducted to verify the analysis and increased noise reduction.