【作者】 傅越千；

【导师】 李章维；

【作者基本信息】 浙江工业大学 ， 控制理论与控制工程， 2009， 硕士

【摘要】 传统的模拟音频广播技术可以方便地将音频信号从演播设备传输到用户终端,但在传输大型广播系统的音频信号时存在一系列的问题,主要表现为:随着传输距离的增加,音频信号的质量会急剧下降,信噪比、高频特性变得差;现代建筑物规模庞大,如何减少布线成本和降低信号衰减已成为模拟音频广播系统中非常棘手的问题;分组广播、故障定位、系统冗余等新功能在传统的模拟音频广播系统中难以实现。随着以太网实时应用技术的发展,传统的模拟音频广播技术将逐步被基于以太网络传输的网络数字音频广播技术所取代。本文在总结分析CobraNet和EtherSound专利音频广播技术的基础上,提出了一种基于以太网络传输的数字音频公共广播技术,适用于对实时性要求不高的音频公共广播。本文的主要工作及成果如下:1.文中研究了多种网络数字音频公共广播的相关技术,主要包括:低延迟的网络音频数据传输方案、先进的网络数字音频公共广播传输协议、高性能的数字音频压缩方案、系统的体系结构和冗余备份等,提出了一种基于音质控制的自适应抖动缓冲控制算法。2.利用网络数字音频公共广播的整体技术方案,搭建了示范系统,研究开发了音频控制服务器应用软件、基于NiosⅡ软核嵌入处理器和μC/OS-Ⅱ实时操作系统的数字音频广播终端和实时语音采集终端。3、详细介绍了基于μC/OS-Ⅱ工实时操作系统、HAL库和LwIP协议的终端设备软件设计及基于SOPC技术的终端设备硬件设计,可实现终端设备的软硬件在线升级,具有非常广阔的产业化前景。4、网络数字音频公共广播示范应用系统涵盖了以下功能:传统广播系统所有功能、动态分区播音、实时插播、移动播音、远程管理、实时监控等。更多还原

【Abstract】 Audio signals can be transmitted conveniently from one terminal to another by the traditional analogue audio broadcast technology.However,it will meet a series of problems to transmit audio signals in a large-scale broadcast system.Firstly,the audio signal quality, including signal-to-noise ratio and high-frequency response characteristics,will decline sharply with the increase in transmission distance.Secondly,due to the existence of huge modern buildings,how to reduce the wiring cost and decrease the signal attenuation in analogue audio broadcast system is a troublesome problem.Thirdly,it is difficult to realize some new functions, such as packet broadcast,fault location,system redundancy and so on.With the development of the Intranet real-time application technology,the traditional analogue audio broadcast technology will be replaced by the IDBP technique gradually.In this paper,based on the analysis of CobraNet and EtherSound audio broadcast technology,we introduced a kind of Intranet Digital Broadcast Platform(IDBP) with independent intellectual property rights,which is suitable for the audio public broadcast with low requirement of real-time characteristics.The main work and the results are as follows:1.The technical proposal of IDBP is introduced.The primary techniques include: low-delayed intranet audio data communication scheme,advanced adaptive jitter buffering control algorithm,applicable IDBP protocol,high-performance digital audio compression scheme,systematic architecture and redundancy backup.2.Based on the IDBP technique,a suit of demonstrating prototype is built.A kind of audio server control software with independent intellectual property rights is designed,and the terminal equipment of IDBP and real-time audio data sampling based on the NiosⅡsoft core embedded processor andμC/OS-Ⅱreal-time operating system are developed.3.The software design of terminal equipment based onμC/OS-Ⅱreal-time operating system,HAL(Hardware Abstraction Layer) library and LwlP(Lightweight IP) protocol is introduced in detail,and the hardware design of terminal equipment based on SOPC(System on Programmable Chip) technique is described.Due to the online update of the hardware/software design and the independent intellectual property rights,the industrial application of the technique is prospective.4.The functions of the designed IDBP system include:all the functions of traditional broadcast system,dynamic partition broadcast,real-time intercut broadcast,mobile broadcast, remote management,real-time monitoring.更多还原