基于VOIP系统语音编码技术的研究

发布时间：2018-03-15 22:38

本文选题：语音　切入点：编码器　出处：《合肥工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：互联网技术给人们的生活方式带来革命性变革。4G时代,互联网语音快速发展,手机客户端利用微信,QQ等软件将语音通过互联网进行传输。多媒体业务不断增长,频率资源变得越来越宝贵,语音占用的数据量也越来越多,因此需要进行压缩编码,语音压缩编码技术的发展决定了VOIP系统通信的未来。目前,互联网语音并没有进行大规模的应用,主要是由于语音质量不稳定,无法满足长途通话的要求。针对上述问题,在互联网中采用G.729编码标准取代传统的G.711,从而实现提高合成语音的质量。论文首先分析语音产生的机理以及对应的数学模型,根据短时语音平稳性的特点,利用平稳随机过程研究G.729编码标准的线性预测模型,并且使用自回归滑动平均模型替换自回归模型进行语音参数的估计,并对两种模型的功率谱进行理论分析及实验仿真,证明自回归平均滑动模型能够进一步提高合成语音的质量；其次,在G.729标准的线性预测模块中,使用滑动平均模型构造出自回归滑动平均模型；最后,以MATLAB为实验平台,通过M文件和GUI的结合,设计出G.729编码标准的仿真界面,并完成两种模型语音信号编解码的仿真实验,对比波形图并对结果进行理论分析。作为一个新兴产业,互联网语音正处于一个导入期与成长期的临界点,由于受到网络环境以及语音编码技术的影响,G.729编码标准的成本较高因此在互联网语音中的应用受到限制。但随着编码技术的不断发展,G.729编码标准将凭借着自身的优势将在互联网语音系统中占有重要地位。文章在VOIP系统研究语音编码技术具有较高的实用价值。
[Abstract]:Internet technology has brought revolutionary changes to people's way of life. 4G era, with the rapid development of Internet voice, mobile phone clients use WeChat QQ and other software to transmit voice through the Internet. The frequency resource becomes more and more precious, and the amount of data occupied by the speech becomes more and more, so it is necessary to carry on the compression coding. The development of the speech compression coding technology determines the communication future of the VOIP system. Internet voice has not been used on a large scale, mainly because the quality of voice is unstable and unable to meet the requirements of long-distance calls. In order to improve the quality of synthesized speech, G.729 coding standard is used to replace the traditional G.711 in the Internet. Firstly, the mechanism of speech production and the corresponding mathematical model are analyzed. The linear prediction model of G. 729 coding standard is studied by using stationary stochastic process, and the speech parameters are estimated by replacing the autoregressive model with the autoregressive moving average model. The power spectrum of the two models is analyzed theoretically and simulated experimentally. It is proved that the autoregressive average sliding model can further improve the quality of synthesized speech. Secondly, in the G.729 standard linear prediction module, the moving average model is used to construct the autoregressive moving average model. Finally, MATLAB is used as the experimental platform. Through the combination of M file and GUI, the simulation interface of G.729 coding standard is designed, and the simulation experiment of speech signal coding and decoding of two models is completed, and the waveform diagram is compared and the result is analyzed theoretically. Internet voice is at a critical point between the import and growth stages. Due to the influence of network environment and speech coding technology, the application of G.729 coding standard in Internet speech is limited because of its high cost. However, with the development of coding technology, G. 729 coding standard will depend on its own. Advantage will play an important role in the Internet speech system. This paper has a high practical value in the research of speech coding technology in VOIP system.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN912.3

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