Digital HDTV broadcasting over the CATV distribution system

This contribution deals with the digital broadcasting of HDTV channels over the cable television (CATV) distribution system, using either single-carrier QAM or an orthogonal frequency division multiplex (OFDM) of many QAM carriers to represent an HDTV channel. Assuming that no error-correcting codes are used, we investigate two distinct cases: in the first case, a few HDTV channels are transmitted among many analog TV channels, whereas in the second case all transmitted channels are HDTV channels. We show that in the first case the transmit power of an HDTV channel can be substantially reduced (by about 10 dB or more) as compared to the transmit power of an analog TV channel, while still maintaining a satisfactory bit error rate (BER). In the second case, not only a considerable reduction of the total transmit power but also a reduction of amplifier cost and an increase of the number of TV channels can be achieved. Single-carrier QAM is found to perform slightly better (at most about 1 or 2 dB) than a multi-carrier QAM.     

残留边带调幅光缆电视光纤传输系统中的频道容量

与传统的电缆电视系统相比，残留边带调幅光缆电视光纤传输系统具有很大的优越性，因而对该系统的研究具有重要的产用意义。文中对ＭＡ－ＶＳＢＣＡＴＶ光纤传输系统的频道容量及其相关因素作了探讨，并导出了一些相关的计算公式。     

Optical digital transmission of HDTV signals for `contribution' use

The key technologies for a 1.2 Gb/s HDTV optical digital transmission system for contribution service use are addressed. A wide-dynamic-range optical receiver is described. Attained average received optical power for an error rate of 10^-9 was from -6 dBm to -38 dBm, with an optical dynamic range of 32 dB. This system provides for transmission lengths from a few meters to up to 80 km. It was confirmed that the system developed is available for interconnecting HDTV equipment within a studio and for dispatching HDTV programs from a production site to a postproduction studio. Scrambled-8B1C NRZ line coding was used to keep clock recovery reliable in the receiver. The line-coding circuit satisfies the BSI (bit sequence independent) property and can be easily implemented using commercial high speed ECL devices     

转播用DWDM高清晰度电视传输系统

1前言日本已拟定于2000年开始进行以数字高清晰度电视和多媒体数据业务为中心的BS（广播卫星）数字广播。为此,除了BS数字广播的各类播出设备需作好充分准备之外,日本广播协会（NHK）正大力推进成为普及Hi-Vision节目制作关键的新闻中心、演播室等以及现场节目制作、转播用的各种必需器材设备的开发研制。作为BS数字广播系统的组成部分,日本广播协会技术局和广播技术研究所开发研制了DWDM（密集波分复用）高清晰度电视传输系统。采用这一系统,多信道Hi·VisionSDI（串行数字接口）信号,用1根光纤即可进行传输。本文拟对DWDM…     

有线电视网双向传输系统

文章概述了有线电视网双向传输的几种接入技术，阐明了有线电视网双向传输光系统的特点，重点描述了光发射机、光放大器、光接收机和有线电视回传信道的应用。本文为某有线电视台双向网改造的实用实例，可为其他有线电视台的双向网改造提供参考。     

1.4 Gbit/s optical DPSK heterodyne transmission system experiment

The authors report the performance of a 1.4 Gbit/s differential phase shift keying (DPSK) coherent fibre system experiment using a balanced receiver. They show that the detection sensitivity as a function of local oscillator power follows the same functional dependence as the theoretical prediction     

立体声数字音频信号光纤传输实验系统的设计

选用非编程芯片设计了一种立体声数字音频信号光纤传输实验系统。系统由信号发送端机、光纤传输链路、信号接收端机组成,并利用2个不同波长的光信号作为载波分别传输左右声道的音频信号。仿真结果表明,系统可实现立体声音频信号的稳定传输。系统的全非编程芯片设计结构,使其各部分电路功能明确和易于更换,适合用于实验教学演示,能让学生更直观地理解数据如何组帧、传输等过程,具有较强的应用价值。     

光纤CATV中调相法抑制相位干涉噪声的研究

本文从理论上研究了附加相位调制抑制相位干涉噪声的方法 ,研究表明 :在光纤AM CATV外调制传输系统中 ,对传输光载波信号引入附加相位调制 ,当相位调制信号的频率为CATV频带的两倍以上时 ,可以有效地抑制相位干涉噪声的发生 ,抑制程度与相位调制度有关。     

Advanced digital HDTV transmission system for terrestrial videosimulcasting

Transmission aspects of the advanced digital high definition television (AD-HDTV) system, for terrestrial simulcast delivery of HDTV are described. In AD-HDTV, two quadrature-amplitude-modulated (QAM) carriers, with different power spectral densities, are employed in a frequency division multiplex (FDM) mode within the standard 6-MHz channel. The resulting spectral shaping allows a larger power to be transmitted, compared to that for a single QAM carrier, for the same level of perceptual interference into cochannel NTSC. The coded video data are split into high-priority (HP) data and standard-priority (SP) data, and the vital information is sent on the appropriate QAM carrier, resulting in a robust audio and video transmission system. The availability is higher in scenarios where the carrier-to-noise ratio (CNR) is above the threshold for HP reception but below the threshold for SP reception; this is important in fringe areas. The NTSC planning factors, suitably modified for HDTV delivery, are used to estimate the coverage area for AD-HDTV. The calculated AD-HDTV coverage area of 54.5 miles is comparable to that for NTSC transmission     

长距离光传输技术的应用和系统设计

１引言在一些地方，广播电视发射台和有线电视台往往建在离电台、电视台播控中心较远的地方，需要考虑如何将广播、电视信号以适当的方式，较小的失真，以及合理的造价传送至发射台和有线台。在建设城阳广播电视信号传输系统时，考虑到既要保证传输质量，又能减少设备造价...     

一种新的光纤语音传输系统设计与实现

简要介绍了语音编解码芯片TLV320AIC23,提出了一种基于FPGA和TLV320AIC23的光纤语音传输系统的设计方案.在QuartusⅡ 7.2开发环境下,采用自顶向下利用原理图与verilog HDL语言相结合的方式,用Altera公司的EP2C35F672C8芯片实现仿真.既可用于光纤通信实验教学,也可作为光纤语音传输系统的试验平台,具有实际应用价值.     

基于光纤通道的IEEE1394光信号传输系统设计

应IEEE1394同光纤通道总线的互联需求,设计了一种基于光纤通道的IEEE1394光信号传输系统。该系统以基于现场可编程逻辑阵列(FPGA)设计的协议映射模块为核心,实现了将IEEE1394信号通过光纤通道进行传输的功能。仿真结果表明,该系统能达到1.062 5 Gb/s的工作速率。     

A coherent optical FDM CATV distribution system

A coherent optical frequency-division-multiplexing (FDM) experimental system for an optical CATV distribution service has been developed. This system employs a channel frequency spacing locked optical FDM transmitter and a random access optical heterodyne receiver. In the transmitter, ten 1.54-μm wavelength tunable distributed-Bragg-reflector laser-diode (DBR LD) modules were FSK modulated with a 400-Mb/s PN pattern. A reference pulse method is used for channel space control. Individual channel spacings for ten LDs are stabilized to 8 GHz. The random access optical heterodyne receiver is realized with a wavelength tunable local DBR LD, polarization diversity reception technique, and random access automatic frequency controller. A current address method realizes the random access function. The results of a ten-channel FDM transmission experiment carried out to evaluate these techniques are presented. It is estimated that over 80 channel high-definition TV signals can be distributed to 2000 subscribers with 500-GHz frequency tunable DBR LD. The feasibility of expanding the subscriber number to over 10000 was confirmed by an experiment with a traveling-wave optical amplifier     

高清晰度电视对天线馈线系统的要求

本文以传输带宽为6MHz的NTSC制为例,阐述了高清晰度电视对天线馈线系统的具体要求,其原则对带宽为8MHz的其它制式也适用。     

模拟中频信号数字化光传输系统设计

概述了模拟信号数字化转换技术的现状和中频信号数字化技术的重要性,主要介绍了中频信号数字化传输系统的实现原理、关键芯片和典型应用电路,并提供了对电路主要环节链路噪声的优化控制方法,可以给初始参与模拟中频数字化设计的人员提供一定的技术参考。     

乡镇有线电视光链路联网设计实例

山东济宁城区辖 12个乡镇 ,总人口 6 0多万人 ,5 6 0多个自然村 ,共 15万户左右。临近城区的一部分用户已纳入济宁市有线电视网直接覆盖 ,另有万余户以ＭＭＤＳ方式进行覆盖。考虑到农村用户分布密度小、距离长的特点 ,在保证系统指标的情况下 ,尽量降低系统成本 ,提高网络质量和可靠性 ,降低运行维护费用 ,为此 ,采用两级光链路方式进行联网 ,即第一级从市有线台前端至乡镇政府所在地以 15 5 0ｎｍ方式进行联网 ,这也是本方案设计的重点 ,第二级是从乡镇至村以 1310ｎｍ方式进行光纤联网。本方案作为《济宁市光纤同轴混合有线电视工程技术…     

5 Gbit/s optical transmission system experiment employing laser amplifier repeater

The performance of a packaged semiconductor laser amplifier has been investigated for use in an optical transmission system at 5 Gbit/s. With optical filtering at the receiver input only small system penalties were found, as expected from the analysis of the dominant noise contributions.<>     

Digital optical CATV system using hubbed distribution architecture

A hubbed distribution architecture based on a bus-star configuration, three-level single single-mode fiber transmission using M-TPC line code, and high-speed IC technology is proposed. The architecture is cost-effective and compact. It is well suited to metropolitan area CATV systems and would allow a gradual transition to a broadband ISDN (integrated-services digital network) subscriber loop in the future. The proposed architecture is applied to a digital optical CATV system prototype. The equipment making up this system consists of a transmitter, hubs including video selectors, and subscriber unit. Two video channels are selected for each subscriber from eight video channels at hub stations. The transmission speed is 900 Mb/s, three-level for the trunk line and 200 Mb/s, three-level for each subscriber loop. Very compact and low-cost equipment is realized by using recently developed high-speed ICs. Experimental results show that the system satisfies requirements and that its commercial application is feasible     

一种基于PON技术的光传输系统方案设计

简要介绍了无源光网络(PON)的工作原理,提出了一种基于PON技术的光传输系统的系统组成,对系统的网络分布结构、传输方式、传输业务类型、帧结构、带宽分配、测距等方面的设计进行了说明,并给出了系统的OLT、ONU原理框图.     

10GBASE-X单通道光传输系统物理层设计

研究了符合IEEE标准的万兆以太网10BASE-X物理层技术,建立了单通道串行光传输系统。对系统原理进行了分析,该系统由数据转换电路和光收发模块组成。利用FPGA实现XGMII和XAUI之间的转换,物理层芯片实现XAUI和XFI的转换,光收发器实现光/电、电/光转换。经实践证明,该单波长光传输系统的数据传输容量达到了10Gbps并给出了仿真结果。