【作者】 杨凯；

【导师】 李方敏；

【作者基本信息】 武汉理工大学 ， 通信与信息系统， 2006， 硕士

【摘要】 随着多媒体语音数码技术、网络通信技术、实时嵌入式软件和硬件技术的进步,结合各类高校、中小学校的实际情况,本文实现了一个高效、安全可靠、满足教学需求的多功能计算机多媒体数字语音教室系统。该系统提供一个先进的多学科授课环境及学习平台,利用视觉、声觉同步教学的手段,使学生多种感官参与学习,提高知识接收的效率,充分发挥计算机辅助教学的作用,从根本上改变并促进师生之间的信息交流,资源共享和教学合作。采用PC机系统所需的成本仍旧很高,阻碍了数字化教学的普及和应用。而采用嵌入式技术则可以在大量降低成本的基础上,同样具备各种所需功能。这种基于嵌入式技术的数字语音教室系统具有音频高清晰、扩展性能好、成本低、教学手段丰富、教学方法灵活多变等优点,具有良好的应用和发展前景。 本文在分析了现有的多媒体数字终端设备和嵌入式技术的基础上,提出了多媒体数字终端的硬、软件体系结构。系统硬件采用高性能ARM920T系列中的S3C2410X CPU芯片,包括LCD、串行通信接口、IIS、ADC等。软件环境采用开放源码的嵌入式Linux操作系统。在操作系统和驱动程序层面上采用优化的数据结构和算法,实现了GUI图形控制界面、VOD点播的功能,并给出了解决相关关键问题的方法,主要包括: 1.灵活、可配置的多缓冲机制音频驱动软件设计与实现; 2.支持拖动功能的触摸屏驱动软件设计与实现; 3.解决数据请求时占用内核时间过长问题的SD卡驱动软件设计与实现; 4.利用S3C2410X通用I/O口虚拟实现PS/2接口; 5.简单的触摸坐标过滤、校准程序,支持MiniGui的图形界面操纵; 6.针对ARM9体系结构,初步探讨了MEPG-4协议实现的优化。 以上底层驱动及图形接口机制功能的实现为上层应用程序提供了很好的支持。最后论文对系统的结构和性能做出了总结和改进完善的建议。更多还原

【Abstract】 With the development of multimedia digital voice technology, communication networks and the real time embedded technology, associating with the special characteristics of all kinds of school, we will build an efficient, security, multifunctional and multimedia digital voice classroom system. The system will provide an advanced multi-subject teaching environment and studying flat. It takes good use of vision and voice synchronization as the way of teaching. The accept efficiency of students can be improved by this means. It is the revolution in education environment which encouraged the information exchange between the teacher and the student, resources sharing and teaching cooperation. When the system uses Person Computer or proprietary chip, the high cost will baffle popularization and application of the digital teaching means. If we use the real time embedded technology, the cost of the system with all kinds of necessary functions will greatly reduce. Based of the real time embedded technology, the digital voice classroom system has the characteristics of small volume, high stable voice quality, good expansibility, low cost, abundant teaching means and flexible and changeable teaching method.On the basic of the existing multimedia digital terminal unit and embedded technologies, we introduce a new software and hardware architecture of multimedia digital terminal. In this model, we adopt S3C2410X CPU of high performanance ARM920T core, including LCD, serial ports, IIS, ADC etc. It adopts open source embedded Linux environment. On the basic of Linux driver, the GUI and VOD functions are realized by using optimizing data structure and arithmetic. At the same time, the methods of the related key problems are provided:1. The audio driver design uses multi-buffer which is flexible and configurable;2. The touch screen driver design supports dragging function;3. The SD card driver design resolves that the kernel is occupied too long by data request;4. Realizing PS/2 interface virtually by using S3C2410X general I/O port;5. The simple touching X/Y-position way to filter and calibrate program and to support MiniGui;6. Based on ARM9 architecture, we only discussed the optimization implementation of MEPG-4 primarily.All of them are provided a good supporting for the top layer. In the end, the conclusions and suggestions on system structure and performance are given out.更多还原