免持聽筒通訊系統之迴音消除暨噪音控制

Abstract

免持聽筒的通訊系統通常遭遇到迴音與環境噪音的影響, 造成通訊品質大打折扣. 本篇論文針對迴音消除器暨噪音控制器的架構, 整理出兩種分類, 並提出平行架構的迴音暨噪音消除器. 我們分析並比較了平行架構與串接架構的殘餘迴音信號收斂強度. 理論的推導與電腦模擬均顯示平行架構高ERLE的性能. 對於汽車內空間響應的量測, 我們提出了實現的方法. 並建議引用分頻平行架構的迴音暨噪音消除器, 來加速汽車內免持聽筒電話迴音與噪音的消除, 並減低運算複雜度,以因應車內空間響應的快速變化.

Hands-free communication systems usually suffer from echo and environment noise. They exacerbate the communication quality. In this thesis, we present a unified approach of echo cancellation and noise control systems which are categorized into two classes. A new parallel structure is also proposed. We analyze and compare the residual error of both parallel and cascade structures. The theoretical analysis and the computer simulations show that the parallel structure has larger convergent ERLE than the cascade structure. We propose the implementation of impulse response measurements and suggest the subbanding parallel structure of echo and noise cancellation in a car chamber. This accelerates convergence rate and reduces the computation complexities.