声回波抵消算法的研究和实现

【作者】 刘世安；

【导师】 郑泰胜；

【作者基本信息】 广东工业大学 ， 信号与信息处理， 2004， 硕士

【摘要】 随着通讯、数字信号处理和大规模集成电路技术的飞速发展，人们对语音通信(如视频会议系统和免提电话等系统)质量的要求越来越高。因此，回波消除技术也就成为世界各大通讯公司竞争的热点技术之一。回波消除技术能有效地解决长距离电话网络、IP电话、免提电话和视频会议等通信系统中的回波问题，很好地改善了语音通信质量，具有广阔的市场前景。 本文主要研究用于声音通讯系统中的声回波抵消技术。声回波抵消通常采用声回波抵消器来实现，最简单的声回波抵消器由自适应滤波器组成。具体方法是用自适应滤波器来估计回波信号，并从麦克风信号中减掉该估计值，从而实现声回波的抵消。 本文内容安排如下： 绪论简要介绍了回波抵消器的背景知识，包括回波的产生机理，自适应回波抵消器的基本原理和构成，最后介绍了本文的主要工作。 第二章主要讨论了回波抵消器中常用的各种自适应滤波算法。对现有主要算法的优缺点进行了分析和评价。 为了在收敛速度和运算量之间得到很好的折中，第三章提出了一种基于仿射投影算法和精确块技术的快速的自适应算法(BEFAP算法)，并对该算法作了详细的分析和研究。 第四章针对会议电视系统终端的具体应用，结合BEFAP算法，给出了一种基于TMS320VC5409DSP实现声回波抵消的软硬件设计方案。 第五章给出声回波消除器的测试结果以及未来工作展望。其中主要测试指标为收敛速度和稳态残留回波。更多还原

【Abstract】 With the rapid development of communication techniques, digital signal processing and VLSI techniques, people demand higher and higher speech quality in communication. So acoustic echo cancellation (AEC) technique has become a hotspot of competition in famous communicaton company all over the world.However, it is not always easy to implement acoustic equipments for communication system with satisfactory speech quality. The technology of echo cancellation has been a very active research field in recent years.This paper is focused on the AEC in communication system,e.g. tele-conference, video-conference.Acoustic echo cancellation is normally achieved by means of an acoustic echo canceller,which,in its simplest form,consists of an adaptive filter which mimics the transfer function of the echo path (or room acoustic ) to synthesize a replica of the echo,and then subtracts the estimation from the combined echo and near-end speech(or disturbance)signal to obtain the near-end signal alone. This paper is organized as follows:The background knowledge about echo canceller such as echo mechanism, basic principle of echo canceller and basic components of echo canceller is introduced in chapter 1In chapter 2 , many kinds of adaptive filter algorithms are dicussed,and their merit and demerit are analyzed .To solve the tradeoff between congverence and computational complexity, BEFAP is proposed in chapter 3,which is based on block-exact processing and affine projection algorithm.Chapter 4 offers hardware and software implementation of the acoustic echo canceller based on TMS320VC5409 DSP ,which can be applied to a terminal of the tele-conference or video-conference.Through simulation and test, Chapter 5 analyzes and evaluates the main performance of the proposed algorithm and gets the result as expected.更多还原