数字电视信号传输技术研究
摘 要
数字电视信号的传输与模拟电视的电波传播截然不同，它是靠由数字“0”和“1”构成的一系列二进制数据来传播的，目前世界上主要通用的传播途径有：地面数字电视传播、卫星数字电视传播及有线数字电视传播。同时，正如模拟电视有PAL\NTSC以及SECAM等制式一样，数字电视也有其主要的传输标准:美国的ATSC、欧洲的DVB以及日本的ISDB。其中前两种标准在世界的全球范围内运用的较为广泛，特别是DVB目前已逐渐成为世界数字电视的主流标准。
本文将就目前的数字电视信号传输技术做一个较为系统的概述。并且对前人在此方面的研究做一个系统性的总结，通过自己在相关领域的实践经验并且结合自身学习到的理论知识，以及前人的经验，对数字电视信号传输技术进行研究。探讨我国目前数字电视信号传输技术的不足，针对现有有线信号传输进行综合测试与评定，根据实验结果，笔者认为数字信号无线传输技术探讨以及、数字信号卫星传输技术是解决目前数字电视信号我国有线传输方式的最佳解决方案。
在整个研究过程中，由于自己在数字电视信号传输方面的相关领域内可能由于缺少更多的实践经验，同时也由于自己在这一方面的理论知识还不够深厚。因此在整个研究过程中或许有一些较为不够准确的地方或者在一些相关技术的定义上和理解上可能有失偏颇。我会在以后的日子里多多加强相关领域内的理论与实践知识，更好地完善自己在这方面的知识体系。
关键字： 数字电视 ；信号传输 ；传输标准 ；传播方式
Digital TV signal transmission technology research
Abstract
Digital transmission of TV signals with analog TV radio wave propagation of very different, it is by the number “0” and “1” consisting of a series of binary data for dissemination, currently major general transmission of the world: the spread of terrestrial digital television, digital satellite television and digital cable TV. At the same time, as some PAL\NTSC and SECAM analog TV standard, also has its main digital TV transmission standard: United States ATSC, European DVB and Japan’s ISDB. The first two standards in the world of more widely used worldwide, in particular DVB has gradually become the mainstream world of digital TV standard.
This article presents a more systematic overview of the current digital TV signal transmission technology. And a systematic summary of previous research in this area, combined with their own study to the theoretical knowledge and previous experience, through their own practical experience in related fields and to study the digital TV signal transmission technology. Explore our current lack of digital TV signal transmission technology and existing wired signal transmission integrated test and evaluation, according to experimental results, I believe that the wireless digital signal transmission technology of the satellite transmission of digital signals is the solution to the digital TV signal China’s wired the best solution for transmission.
In the entire research process, because of their own in the digital TV signal transmission related field may be due to the lack of more practical experience, but also because of their own in the aspects of the theory of knowledge is not deep. Therefore in the entire research process may have a more accurate enough to place or at some technology related to the definition and understanding may be biased. I will be in the days after a lot of field enhancement associated with the theory and practice of knowledge, to better improve themselves in this knowledge system.
Keywords: digital television; signal transmission; transmission standards; transmission mode
目 录
0 引言……………………………………………………………………1
1 绪论……………………………………………………………………2
1.1研究背景…………………………………………………………………………2
1.1.1数字电视在全球的发展………………………………………………………2
1.1.2我国数字电视发展现状及优势………………………………………………2
1.2文献综述…………………………………………………………………………4
1.2.1数字电视技术研究现状………………………………………………………4
1.2.2数字信号传输技术研究现状…………………………………………………5
1.3研究的意义及必要性…………………………………………………………6
1.4研究内容及思路……………………………………………………………6
1.5创新性与不足…………………………………………………………6
2 数字电视信号概述……………………………………………………8
2.1数字信号的产生………………………………………………………………8
2.2数字电视信号概述………………………………………………………………9
2.2.1数字电视信号传输标准………………………………………………………10
2.2.2 目前数字电视信号最新科技成果……………………………………………11
2.3数字电视信号传输特点…………………………………………………………11
2.3.1数字信号的失真及其误码控制………………………………………………11
2.3.2网络相位特性对数字信号的影响……………………………………………12
2.3.3数字信号优点…………………………………………………………………13
3 现有数字电视信号传输基础及不足之处……………………………14
3.1数字信号传输中的衰落与干扰…………………………………………………14
3.1.1路径损耗………………………………………………………………………14
3.1.2脉冲干扰………………………………………………………………………14
3.1.3抖动与漂移……………………………………………………………………14
3.1.4反射干扰………………………………………………………………………14
3.1.5马赛克现象……………………………………………………………………14
3.2数字信号的基带传输……………………………………………………………14
3.2.1基带信号与信道特性…………………………………………………………15
3.2.2改变编码码型…………………………………………………………………15
3.2.3改变脉冲波形…………………………………………………………………16
3.2.4使用随机序列进行扰码………………………………………………………16
3.2.5减少冗余码……………………………………………………………………
3.2.6时域均衡器……………………………………………………………………16
3.3数字信号的载波传输与数字调制技术…………………………………………16
3.3.1幅移键控（ASK）……………………………………………………………16
3.3.2频移键控（FSK）………………………………………………………………17
3.3.3相移键控…………………………………………………………………17
3.3.4QPSK调制原理………………………………………………………………17
3.3.5QAM调制原理………………………………………………………………17
3.4有线数字电视信号传输不足之处………………………………………………17
3.4.1占用频带宽……………………………………………………………………17
3.4.2传输稳定性难以保障…………………………………………………………18
3.4.3安全性不足……………………………………………………………………18
3.4.4安装成本较高…………………………………………………………………18
4 改进措施及解决方法…………………………………………………………20
4.1利用光缆传输有线电视信号……………………………………………………20
4.2 数字信号无线传输技术探讨…………………………………………………21
4.3 数字信号卫星传输技术探讨…………………………………………………23
4.3.1现状……………………………………………………………………………23
4.3.2 网络共享CW接收……………………………………………………………23
4.3.3卫星共享CW接收……………………………………………………………23
4.3.4 缺陷存在的原因………………………………………………………………23
4.3.5解决思路………………………………………………………………………24
5 数字电视信号传输未来发展趋势和方向……………………………25
5.1光纤通信…………………………………………………………………………25
5.2移动通信…………………………………………………………………………25
5.3微波中继通信……………………………………………………………………25
5.4数字电视技术发展方向…………………………………………………………26
结束语…………………………………………………………………28
致 谢……………………………………………………………………29
参考文献…………………………………………………………………30
