地面数字电视广播单频网系统及传输覆盖

本文研究地面数字电视广播单频网,分析其系统组成和传输覆盖,对工程实施和优化完善提出建议。地面数字电视广播单频网是我国广播电视体系的重要组成部分。单频网在传输覆盖工程中的应用十分常见,不仅可以提高频率规划效率,还可以解决覆盖盲区问题,提高覆盖率。     

地面数字电视广播单频网应用实践

对地面数字电视传输标准的单频网性能进行了分析,并结合地面数字电视单频网的实际测试结果,提出地面数字电视单频网覆盖中的若干建议.     

对数字电视地面广播编码方法的思考

合理利用MPGE-2、MPEG-4编码方法，使数字电视地面广播既能支持多套节目的静态接收又能支持移动电视。一个单频网可以替代现有的无线覆盖，同时解决移动电视的接收问题，实现模拟电视地面广播到数字电视地面广播的转变，真正形成多套频道、多功能的数字地面广播网。     

地面数字电视广播单频网的应用

作为数字广播电视的一种无线电发射台,单频网的出现大大地节约了频率资源,提高了频谱的利用率,就地面电视广播数字化的发展以及单频网的有关问题进行了论述。     

贵州广播电视台地面数字电视无线覆盖系统应用

随着地面无线模拟电视的全面停播,地面无线数字电视成为无线覆盖的主要手段,它具有成本低、传输快捷、抗干扰能力强以及覆盖范围广的特点。结合贵州地区喀斯特地貌特点,分析研究地面无线数字电视系统的卫星接收、前端传输、单频网以及发射等各部分,讨论系统的应用与特点。     

地面数字电视广播覆盖的研究

近年来,随着社会的进步和科技的发展,我国数字化技术也发展到了一个新的台阶,数字化技术在各个领域中得到了极为广泛的应用,地面数字电视广播有着众多的先进之处,但也受制于经济基础和现有电视传播设备及接收设备的广泛使用。本文围绕地面数字电视广播覆盖展开讨论,对一些问题进行了分析。     

利用卫星转发组建地面数字电视广播单频网

介绍了利用卫星转发编码正交频分复用(COFDM)信号组建地面数字电视广播单频网,及其试验情况,并进行了理论性的计算和研究.分析探讨了这种组网方案的特点和局限性,指出了其适用的范围和场合.     

地面无线数字电视传输覆盖的研究

对地面无线数字电视传输覆盖技术的特点、组网方式等进行了探讨,通过分析和比较,从而为各地地面数字电视无线覆盖的规划和发展提供参考。     

地面数字电视广播单频网的智慧运维平台建设

以智慧广电工程为牵引,打造智慧广电媒体,发展智慧广电网络,是我国广播电视领域发展的重要方向。地面数字电视广播单频网智慧运维平台,作为智慧广电网络建设的基础内容,在提升地面数字电视广播网络智慧化运维方面发挥着关键性的作用。基于此,结合智慧广电建设实际,在介绍地面数字电视广播单频网构成、特点的基础上,重点设计单频网智慧运维平台的架构,结合平台运行的实际情况,对平台发挥的主要功能进行归纳总结,为智慧运维平台建设提供相关内容参考。     

河北省地面数字电视广播频率规划研究

结合河北省地面数字电视广播频率规划研究工作,通过省级、市级单频网规划实例,对地面数字电视频率规划的原则与规划步骤进行了总结,对频率规划所涉及的技术参数和规划方法进行了重点分析,提出了省级地面数字电视频率规划中分别建设省级单频网、市级单频网、县级多频网的规划方案。     

Single carrier digital terrestrial television broadcasting

A transmission system for digital terrestrial television broadcasting has been designed. This system is based on the European cable system but uses stronger error correction and better equalization. The stronger error correction is a concatenation of Reed Solomon coding RS [204,188,17] and convolutional coding with R_conv=1/2, 2/3, 3/4, 5/6 and 7/8. The algorithm which is used for convolutional decoding is the Viterbi algorithm. To provide the Viterbi decoder with soft decision information, every symbol bit will be expanded with two soft decision (reliability) bits. The modulation scheme of the terrestrial transmission system is 64-QAM square root raised cosine filtered with a roll off factor α=0.15. The mapping of the symbols into the 64-QAM constellation is a Gray-mapping over the complete I,Q-plane. In this paper the performances of the terrestrial transmission system are simulated and analyzed     

地面数字多媒体电视广播传输系统研究

描述地面数字多媒体电视广播传输（DMB-T）系统结构，对该系统的分层传输特性、同步性能、抗干扰性和抗多径性能进行了讨论，同时介绍了设计实现的流程。     

A concept of digital terrestrial television broadcasting

The future terrestrial television broadcasting system should support the transmission of a digital HDTV signal with a high spectral efficiency. In addition, this system should maintain graceful degradation as the actual analog systems, and should be compatible with the SDTV. The system compatibility can be achieved by using a hierarchical HDTV source-coding scheme that can provide at least two (HDTV, SDTV) or three (HDTV, EDTV, SDTV) hierarchy levels: SDTV image quality will be expected for portable receivers, and HDTV/EDTV image quality will destinate to stationary receivers with roof-top antennas. Taking into account the receivers' antenna gains and the different channel conditions, there will be a difference of 25–30 dB between the received powers of the stationary and the portable receivers. Therefore, the design of a powerful and a suitable transmission scheme for the future broadcasting of the digital HDTV signal will be a technological challenge. In this article we describe a concept of a flexible reconfigurable hierarchical digital terrestrial TV broadcasting system for clear and taboo channels. The flexibility of the proposed scheme easily permits the receivers to support different reconfigurable modes: One HDTV program or multi-programming EDTV or SDTV (for fixed receivers up to 5 × SDTV in clear and up to 2 × SDTV in taboo channels; for portable receivers up to 2 × SDTV.) The system achieves a high interoperability with the Satellite Baseline system. It maintains a graceful degradation and provides a hierarchical complexity. It is based on a concatenated coding scheme. The inner code of the concatenated coding scheme is combined with multi-resolution modulation. The basic constellation is a 64-QAM, which will be operated in clear channels. It can be reconfigured to a 16-QAM in the case of taboo channels. The principle of OFDM with very rugged frequency/time synchronization mechanisms is used to combat the frequency selectivity and the co-channel interference (CCI) in the channel. Known pilot symbols are sent regularly in order to perform coherent detection.The authors are within the RACE-dTTb and the German HDTV-T project.     

数字电视地面广播信道的均衡技术

作为数字电视地面广播的一种关键技术,均衡技术可以有效去除符号间干扰,保证视频流的优质传输,尤其确保了大容量、高速可靠移动接收的实现。本文对目前单载波和多载波传输方案中的均衡原理进行了描述,分析了现有方案的不足,并结合盲均衡提出了数字电视均衡技术的发展前景。     

Digital television terrestrial broadcasting

Digital transmission will change the way television channels are allocated and will force broadcasters to master a new set of parameters for optimizing service coverage. This article discusses modulation and channel coding issues related to digital television terrestrial broadcasting (DTTB), such as data throughput, spectrum efficiency, single- and multicarrier modulations, interferences under simulcasting conditions, multilayer services, and DTTB coverage. Current advanced television (ATV) research for terrestrial broadcasting in the VHF/UHF bands is converging toward a fully digital implementation. In a digital ATV system, the digitized high definition video sources, with raw bit rate of up to l-Gb/s, are compressed using source coding techniques based on the discrete cosine transform (DCT) coding. The output data rate of the video source encoder, with present technology, is typically 15 to 20 Mb/s. This data rate is sufficient to provide a satisfactory distribution quality video service     

Coded OFDM with transmitter diversity for digital television terrestrial broadcasting

Space-frequency coded (SFC) and channel coded orthogonal frequency-division multiplexing (COFDM) is considered under narrow-band interference (NBI). Analytical expressions for the bit error probability (BEP) are derived for OFDM with SFC in a frequency-selective fading environment. It is shown that SFC increases the resistance of COFDM against the NBI and reduces the BEP considerably. Specific attention is paid to Digital Terrestrial Television Broadcasting (DTTB), and the associated coding gains are discussed.     

中国地面数字电视广播的普遍服务策略

在这错综复杂与风云变幻的国内外电信新环境中．如何把握好发展方向及战略决策已成当务之急。“领航论坛”这一栏目．即期望提供一种机会，使电信．特别是无线通信领域中引领潮流的重量级资深决策者发表战略决策真知灼见．为无线通信产业．市场及新技术、新业务的持续、快速、稳妥、健康发展领航导向。如众所知，上世纪30—40年代兴起的黑白电视使人类生活发生了革命性变化．至50年代后又产生了新飞跃，     

符合中国数字电视地面广播标准的前向纠错码编码器设计

文章提供了一种符合中国数字电视地面广播标准中的前向纠错码BCH-LDPC级联编码器的硬件实现方案.设计充分利用了此LDPC码的G矩阵的准循环特性,在结构、存储空间和时序上得以较大的优化.此结构也具有一定的灵活性,能通过对G矩阵列划分改变其并行度,从而改变速度和面积上的折中.并且通过在控制电路中设定不同的状态跳转条件实现不同码率的编码要求,使编码器大部分模块得到了重用.     

一种新的地面数字多媒体/电视广播传输系统

针对传输信道线性时变的宽带传输信道特性，设计了一种时域同步正交频分复用（简称TDS－OFDM）的多载波调制方式。这种调制方式既适用于具有多径干扰和多普勒频移的地面数字电视广播传输信道，也适用于其它宽带数字传输系统。为了进一步提高传输效率，提出的地面数字多媒体／电视广播DMB－T传输系统还采用了最新的纠错编码和交织编码技术，在额定的8MHz带宽中，净载数据传输率可达32．511Mbps。     

Analytical modeling and simulation of phase noise interference inOFDM-based digital television terrestrial broadcasting systems

This paper deals with the problem of modeling of phase noise in OFDM systems and the impact it may have on the bit error rate performance of such systems subject to a number of system variables and to a number of channel conditions which may be encountered when such systems are deployed for certain applications such as high speed wireless LANs and Digital Television Terrestrial Broadcasting (DTTB). The phase noise processes, the sources of which are the transmitter's and receiver's local oscillator, are modeled using what is believed to be commercially realizable phase noise masks. Such masks represent the long-term averaged power spectral densities of the local oscillator output signal