基于EPON的数字电视传输系统

在分析HFC与EPON有关性质的基础上,提出基于EPON的数字电视传输方法。叙述了系统的组成与各模块的功能及系统的实现过程。讨论了频道切换等关键技术,并设计与实现了利用组播的频道切换机制。给出了一个实验系统的各芯片选型。     

基于EPON的分布式光纤光栅传感网络研究

提出了一种基于以太无源光网络(EPON)的光纤布拉格光栅(FBG)传感网络多传感通道切换控制方案。控制传感通道切换的多个光开关分别与EPON系统中的多个光网络单元(ONU)相连,利用各ONU间严格的时间同步特性在各ONU控制下实施对多个光开关的同步切换控制,实现各FBG传感通道与传感解调模块间的有序连通。实验结果表明,此方案的稳定性较好,并且具有较灵活的扩展特性。     

双模ONU模式切换方案的设计与实现北大核心

针对双模ONU(光网络单元)注册前如何正确识别当前系统的问题,提出了两种双模ONU的切换方法,结合双模ONU可能出现的切换情况,选择适合当前切换场景的切换方法,设计并实现了双模ONU自动识别当前GPON(吉比特无源光网络)/EPON(以太无源光网络)系统的方案,从而解决了运营商采用混合方式部署接入系统的问题,同时也为实现两种技术的融合提供了参考。     

基于EPON的视频统计复用器的研制

在介绍统计复用原理的基础上,提出基于EPON的TV Over IP系统中视频统计复用器的设计思想,并叙述其硬件构成及其软件实现.讨论了利用组播原理实现频道切换的关键技术.     

EPON技术在移动通信接入中的应用

目前EPON在广电网络中的应用已比较成熟,但在移动通信领域仍不太成熟.针对目前的移动通信接入体系存在的种种弊端,如在小区间切换困难,信号不稳定,存在延迟等,EPON技术逐渐被引入移动通信领域.本文介绍了EPON在移动通信接入中的应用及特点.     

EPON系统中嵌入式系统的研究与应用

阐述了千兆以太无源光网络（EPON）系统。结合EPON系统的功能要求，指出嵌入式Linux系统是EPON系统软件设计较好的平台，提出了嵌入式Linux系统在EPON系统中的应用。     

百兆EPON系统的FPGA设计

在分析EPON多点控制协议(MPCP)的基础上,对EPON的层次模型以及各项关键技术进行了研究,设计了EPON系统的FPGA实现方案,研制了一套带局端设备(OLT)和用户端设备(ONU)的百兆EPON实验系统。测试结果表明,系统性能达到了EPON技术对丢包率和带宽的要求。     

配网自动化系统中EPON分光器的研究

随着智能电网的深入开展,配电自动化系统作为不可或缺的一部分,各地电力公司都大力整改或搭建自己的配电自动化系统。由于EPON采用点到多点结构而且具有低成本、高带宽、扩展性强等功能,因此EPON在配电自动化系统中被大量使用。分光器是EPON系统中重要组成部分,分光器的选择直接影响到EPON系统的效果。本文主要对EPON系统中的分光器进行了相关的研究。     

浅谈EPON技术在有线电视通信网络中的应用

有线电视通信网络相对于传统无线通信网络具有图像高清,客户满意度高等特点,而且能在有效实现各频段电视节目变更前提下,确保电视信息流实时切换。EPON技术是有线电视通信网中常见技术,因其有效结合以太网传输效率高、成本低,扩展性好等特点,被广泛地应用在电视通信网络。文章先简介EPON技术特点,后详细分析EPON技术在有线电视通信网络中的应用,对相关技术发展提供一定程度的参考依据。     

基于AES加密算法的1.25Gb/sEPON下行加密研究

介绍了AES-128算法的加、解密原理,从明文和密钥角度分析了AES加密算法的雪崩效应,提出了增量式密钥更新方法,通过在新旧密钥加密的密文之间插入密钥更新符,引导接收端无缝切换密钥。重点研究AES-128加密算法在1.25Gb/s EPON中的应用,通过FPGA和SFP光收发模块搭建实验平台,实现EPON物理层下行数据的加密、解密和密钥更新功能,保证了EPON下行通道数据的安全性。     

IT服务与有线行业信息化

在完成"双改"后,有线电视行业开始将关注点转向数字电视增值服务,但对于面向互联网的IT增值服务关注不够.事实是IT服务和IT服务外包在迅猛地发展,即使电信行业也开始向"综合信息服务提供商"转型.有线行业在经营好自己"花园围墙"的时候,应该考虑如何将自己传统的业务与新兴的IT服务结合起来,"兼容"互联网,依托开放的技术、丰富的内容、优质的服务谋求更大的发展.     

基于WiFi的电视副机遥控器设计

通过对WiFi无线数据通信系统的分析,探究其在广播电视频道遥控中的运用,针对电视副机不能独立选台的不足,提出了一种基于WiFi的电视副机遥控器方案。方案中手机选台控制软件发送选台控制命令,利用无线的方式传输至控制系统中的WiFi模块,控制系统对数据进行处理后通过遥控器按键拉出引线排传输至遥控器内部实现对主机频道的控制,从而使副机频道随主机的改变而改变。解决了数字电视副机不能独立选台的问题,使用户可以随时随地跨房间自由切换电视节目。     

Channel characterization and television field strength measurements

The new standard in North America for the advanced television (ATV) transmission system will be selected in 1996. The new ATV system is expected to co-exist with the conventional NTSC television system for many years to come. Simulcasting of the two systems will require a good understanding of the channels used. In this paper, a method to characterize a channel using the ghost canceling reference (GCR) signal is presented as well as the method used to conduct field strength measurements of television channels. The channel characterization gives us the time and frequency response of channels. The field strength measurements show the power variation of the signals that are transmitted through a channel over a period of time. The results obtained from field tests for a number of channels and with different polarization of transmitter's and receiver's antennas are then presented. The results for the channel characterization of a cable network using the GCR signal are also presented     

浅析AVS+技术在数字卫星广播中的应用

四川广播电视台拟将四川综合频道（卫视）高清节目上星覆盖全国,拟采用将四川综合频道（卫视）高清信号通过中广网异地传输至上海广播电视台进行加密,同时为了推动AVS+技术在广播电视领域的应用,上海广播电视卫星地球站拟将东方卫视高清、四川综合频道（卫视）高清频道和纪实高清以MCPC方式,通过上海卫星地球站上行系统进行上星传输。     

Local distribution for IMTV

The local distribution system for an interactive multimedia television (IMTV) system builds on a fiber-to-the-curb (FTTC) architecture that delivers the IMTV signals to and from the home over telephone wiring and coaxial cable. The downstream IMTV channel, from the curb to the home, operates at a data rate of 51.84 Mbps, and the upstream channel, from the home to the curb, operates at a data rate of 1.62 Mbps     

The Japanese scene [digital HDTV]

Japan is the only country, so far, to be actually broadcasting high-definition television services. MUSE (multiple sub-Nyquist sampling encoding) is the basis for systems applying bandwidth compression to the transmission of both analog and digital signals. It encodes a signal of 1125 lines and 60 fields per second, a high-definition television (HDTV) signal into an 8-Hz bandwidth. Experimental MUSE broadcasts started in 1990 and have continued ever since. Meanwhile, work has been in progress in areas other than MUSE. Enhanced-definition television, a terrestrial system, is entering its second generation. Integrated digital broadcasting looks to spin many services into a single digital thread for transmission over a single channel. Digital sound broadcasting and hierarchical television transmission will also come in for consideration. The MUSE system depends on digital technology for signal processing, but the HDTV signal that is broadcast is analog, the outcome of frequency modulation     

有线数字电视信道编码技术

在传输有线数字电视信号的过程中,为保证信号正常无误地传送,采用的核心技术就是有线数字电视信道编码技术。在介绍有线数字电视及信道编码的基础上,详细分析讨论了有线数字电视信道编码中的数据随机化、RS编码和卷积交织等技术的原理及其参数的意义。     

Digital video broadcasting

A new kind of “wireless video” is currently entering consumers' homes-digital television. The term digital video broadcasting (DVB) is used as a synonym for digital television in many countries of the world. Whereas one may tend to think that digital television means just a new, digital, form of signal representation not necessarily affecting the information content of what one has always called TV, the truth is that digital television becomes multiple-channel data broadcasting. This article reviews some of the results of the work in the worldwide DVB Project and explains some of the fundamental concepts behind the work of this group. It then concentrates on the terrestrial transmission system (DVB-T) as one example of the many transmission technologies DVB has developed over the last few years. The COFDM modulation scheme which is a key ingredient of DVB-T is described in some detail. The performance of the system is presented. The use of DVB for data broadcasting and the accompanying return channel technologies are explained     

HIGH-EFFICIENCY CODING FOR PAL COLOR TELEVISION SIGNAL

Proceeding from the specific characteristics of PAL television signals adopted in China this paper points out that if the fs = 2fsc of sub-Nyquist sampling and DPCM encoding is used for PAL complete signal and if the blanking time is utilized to transmit code of effective area, it is possible to transmit a color TV signal over PCM three-group channel.