本論文說明如何應用嵌入式單晶片(TMS320C6711DSK) 於助聽器系統上，實現以小波係數臨界法來消除背景噪音的技術。當要消除語音上的雜訊時，必須使用MATLABTM Wavelet toolbox分析設定以得到所需要的臨界值。且在消除雜訊的過程中，必須依據統計特性的經驗值來進行最佳臨界值的選取。若硬體製作需要達到即時消除雜訊時，建議使用計算較簡單的Haar小波演算法。
從研究結果可看出此系統確實能夠達到將語音訊號成份大部分保留，並在以小波係數為架構的FIR數位濾波器，於切頻拆解的過程中消除噪音。當噪音和語音訊號被放大的同時，一般助聽器的使用者在吵雜的環境下無法清楚的聽到語音訊號，而以設定小波係數臨界法改進的數位助聽器則可以明顯分辨語音訊號或噪音的差異。

In this paper, a noise reduction technique that implemented with the TMS32C6711DSK system for digital hearing aids is described. The technique uses an algorithm based on a wavelet coefficient threshold method to reduce the background noise. To eliminate the noise in the speech signals, an analyzable threshold is given from the Wavelet toolbox of MATLABTM. In the process of noise reduction, the setting of an optimal threshold relies on statistical data from experiences. If real-time process is required in the hardware (TMS32C6711DSK) implementation, the de-noising algorithm based on a choice of the Haar’s wavelets is recommended for that it has simpler computing.
The results show that the system can reserve the most of human speech signal in sub-band decomposition process. When the noise and speech signal are amplified at the same time, hearing aid users can’t clearly hear speech signal in noisy environment. By using the wavelet coefficient threshold, we can discriminate the difference between speech signal and noise.

中文摘要……………………………………………………………...…………………….......I
英文摘要……………………………………………………………………..…………….…..II
誌謝……………………………………………………………………………………...…….III
目錄………………………………………………………………………………...................IV
圖……………………………………………………………………………………………….V
第一章 緒論…………………………………………………………………………..……1
一、 研究動機…….……………………………………………………………………1
二、 研究目的 ….…………………………………………………………………….1
第二章 小波理論………………………………………………………………………….2
2.1 簡介……………………………………………………………………………2
2.2 短時傅氏轉換-STFT簡介………………………………………………….. 2
2.3 小波特性………………………………………………………………………5
2.4 小波函數的種類………………………………………………………………7
第三章應用小波轉換之語音雜訊消除演算法………………………………………. 13
3.1 簡介……..….................................................13
3.2 小波組態轉換雜訊消除系統.………………………………………………14
3.2.1 簡 介 ……………………………………………………………..........14
3.2.2 小波係數臨界演算法 …………………………………………………15
3.2.3 語音信號分析與雜訊消除的原理…………………………………… 16
第四章軟硬體共同設計……………………………………………………………… 17
4.1 演算法構成的方式………………………………………………………… 17
4.2 TMS320C6711DSK之硬體架構………..……………………………………..21
第五章 系統測試與結果……………………………………………………………….24
5.1軟體模擬……………………………………………………………………24
5.2 實際語音之處理結果……………………………………………………..29
第六章 結論與未來展望………………………………………………………………34

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