臺灣博碩士論文加值系統

本論文主要針對主動式噪音消除系統進行研究，在理想的情況下，主動式噪音消除器可達到很好消除噪音的功能；然而在實務上系統本身可能是非線性和非時變的，訊號且會經過A/D、麥克風、喇叭與傳播路徑等，這些都會造成特性變差。而在本論文中，我們主要考慮第二路徑的影響，所以為了補償第二路徑的方法其理論為FXLMS演算法，本論文並採用離線式與線上式兩種方法來估測第二路徑。
最後本論文提出具噪音源觀測與無噪音源觀測之主動式噪音消除系統，此系統是包含訊號的路徑補償濾波器、噪音消除濾波器與預測濾波器三種調適濾波器。其中具噪音源觀測是指噪音經由感測器去擷取噪音，並利用誤差感測器去取得殘餘訊號，用此架構並使用噪音消除濾波器來達到噪音消除；而無噪音源觀測是利用預測濾波器來消除此噪音。此系統架構並應用Matlab軟體做數值模擬驗證其效能與特性。

This thesis is mainly devoted to study of active noise cancelling systems. On ideal situations, active noise cancelling systems achieve very good performance. However, a real-word noise canceling systems may have nonlinear and time varying property. The signals involve pass through A/D, microphone, loudspeaker and audio propagating with unknown characteristics, which substantially decrease the system performance. In this thesis, we have considered the effect of secondary path. On the system modeling, which can be by the FXLMS algorithm. An off-line scheme and an on-line scheme have been delivered to estimate unknown secondary path.
In this thesis, we propose a noise cancelling system scheme with both observed and unobserved noise sources. This system has three adaptive filters that are compensation, noise canceling and predictor. In such noise canceling system, the observed noise sources mainly deliver sensor, which passes through an adaptive filter to extract the noise component in original signal. As for unobserved noise sources, noise estimated schemes are utilizing adaptive predictor to reduce noise component. This system structure utilizes Matlab that simulates to identify performance and property.

目錄.....................................................Ⅰ
圖表索引.................................................Ⅲ
第一章 緒論..............................................1
1.1 研究動機.............................................1
1.2 文獻回顧.............................................4
1.3 內容大綱.............................................5
第二章 調適濾波器........................................7
2.1 簡介.................................................7
2.2 橫貫式適應性濾波器之基本原理.........................7
2.3 最小均方LMS演算法...................................12
2.4 正規化最小均方NLMS演算法............................13
2.5 遞迴式最小平方RLS演算法.............................15
2.6 各演算法收斂速度與計算量之比較......................17
第三章 主動式噪音消除系統之架構.........................20
3.1 系統簡介............................................21
3.2 具訊號源觀測的適應性噪音消除之基本原理..............22
3.3 無訊號源觀測的適應性噪音消除之基本原理..............28
第四章 第二路徑的分析...................................34
4.1 第二路徑簡介........................................35
4.2 FXLMS演算法.........................................37
4.3 第二路徑的估測......................................39
4.3.1 離線式估測技術....................................40
4.3.2 線上式估測技術....................................48
第五章 具噪音源觀測與無噪音源觀測之主動式噪音消除系統...64
5.1 系統簡介............................................64
5.2 系統模擬............................................65
第五章 結論.............................................91
參考文獻................................................93
作者簡介................................................95

參考文獻
1. C. M. Harris, Handbook of Acoustical Measurements and Noise Control, 3rd ed. New York: McGraw-Hill, 1991.
2. S. J. Elliott and P. A. Nelson, “Active Noise Control,” IEEE Signal Proc., pp.12-35, Oct. 1993.
3. S. M. Kuo and D. R. Morgan, “Active Noise Control: A Tutorial Review,” Proceedings of the IEEE, vol. 87, NO. 6,pp. 943-975, June 1999.
4. S. J. Elliott, and P. A. Nelson, “The active control of sound,” Electronics & Communication Engineering Journal, Vol. 2, Issue 4, pp. 127-136 Aug. 1990
5. C. R. Fuller, and A. H. Flotow, “Active control of sound and vibration,” IEEE Control Systems Magazine, Vol. 15, Issue 6, pp. 9 -19 Dec. 1995.
6. B. Widrow and S. D. Stearns, Adaptive Signal Processing, Englewood Cliffs, NJ: Prentice-Hall, 1985.
7. S. Haykin, Adaptive Filter Theory, Prentice-Hall, 1996.
8. J. C. Burgess, “Active adaptive sound control in a duct: A Computer Simulation,” J. Acoust. Soc. Am., vol. 70, pp. 715-726, Sep. 1981.
9. B. Widrow, D. Shur, and S. Shaffer, “On adaptive inverse control,” in Proc. 15th Asilomar Conf., pp. 185-189, 1981.
10. O. J. Tobias, J. C. M. Bermudez, and N. J. Bershad, “Mean weight behavior of the filtered-X LMS algorithm,” IEEE Transactions on Signal Processing, Vol. 48, Issue 4, pp. 1061-1075, April 2000.
11. P. Lueg, ”Process of silencing sound oscillations,” U. S. Patent 2 043 416, June 9, 1936.
12. H. F. Olson and E. G. May , “Electronic sound Asorbers, ”Journal of the Acoustic Society of America,Vol.25, No.6 pp.1130-1136, 1953.
13. S. J. Elliott, C. C. Boucher, and P. A. Nelson, “The effect of acoustic coupling on the stability and convergence in the active control of sound,” in Proc. Inter-noise, pp. 157-160, 1991.
14. J. F. Abbott, “Acoustical design criteria for active noise-control systems,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Vol. 5, pp. 630-633, 1993.
15. L. J. Eriksson and M. C. Allie, “Use of random noise for on-line transducer modeling in an adaptive active attenuation system,” J. Acoust. Soc. Am., vol. 85, pp. 797-802, Feb. 1989.
16. S. M. Kuo and D. R. Morgan, Active Noise Control Systems ---Algorithms and DSP Implementations, New York: Wiley, 1996.