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。     

双向有线电视网上行通道中的噪声及其降低措施

1　双向有线电视网上行通道的概念双向有线电视网目前均采用ＨＦＣ网络结构 ,其组成如图 1所示 ,主要由前端设备、光发射 /接收机、光纤、同轴电缆网等组成。具备双向传输功能的有线电视网必须有双向传输通道亦即上行通道和下行通道 ,上行通道是指从用户端到有线电视台前端的网络通道 ,主要由用户到光节点的同轴电缆网和光节点到前端的上行光纤两部分组成。用户端的信号经含双向放大器的同轴电缆网到达光节点 ,再经上行光纤到达有线电视台前端进行交换处理。双向放大器由正向放大器和反向放大器以及两个双向滤波器组成 ,其传输过程为前端信…     

有线电视网中AM光纤传输设备及使用（上）

有线电视网中ＡＭ光纤传输设备及使用（上）林敦随着ＣＡＴＶ网的扩展，传输距离越来越远，功能越来越复杂，使同轴电缆传输难以满足发展的需要。而采用ＡＭ光纤传输则是解决以上问题的一个最好方案。最简单的ＡＭ光纤系统由一个光发射机，一段光缆和一个光接收机组成。如...     

调频光端机原理及实现

主要介绍电视信号通过光纤传输的原理和应用电路。调频光端机采用的是脉冲频率调制,包括发端机和收端机。发端功能是将信号经过调制后,把电信号变换成光信号,经光源发射出去。收端作用是将接收的光信号转换成电信号,鉴频解调,放大输出。信号可长距离无中继传输,明显改善电视传输质量。图像信噪比高、失真小。     

基于压缩脉冲载波的远端上变频光载射频系统

提出并实现了一种用光纤色散压缩脉冲为载波的上变频射频光载系统。该系统把传统的连续光载波替换为频率啁啾脉冲,利用传输光纤色散压缩脉冲宽度,增强谐波分量,使脉冲载波上的信号在接收端转换到脉冲高次谐波上,从而实现了远端上变频。该方法的特点是用低频本振就可实现高频微波信号的产生,发射端无需电倍频器、混频器,接收端只需用滤波器选择所需频率信号,系统结构简单。应用该方法实现了2Gbit/s信号经60km普通单模光纤传输后远端上变频到16GHz、经过5.4m无线传输后误码率低于10-8的射频光载系统,系统中只有一个光功率放大器,无光在线和预放大以及光滤波器和色散补偿。     

光纤在有线电视技术中的应用

本文介绍了光纤在有线电视网中的应用，光发送接收端机的结构和性能，光纤传输系统的设计以及光纤系统的优势。     

有线电视网中AM光纤传输设备及使用（下）

有线电视网中ＡＭ光纤传输设备及使用（下）林敦（武汉市电子科学研究院）ＡＭ光纤传输系统计算计算公式：１．光发射端机输出光功率ｘｍｗ与光信号ｄＢｍ换算公式：ｄＢｍ＝１０Ｌｇｘｍｗ／１ｍｗ例：４ｍｗ相当于１０Ｌｇ·４ｍｗ／１ｍｗ＝６ｄＢｍ２．一对光发送／接...     

海底远程激发光放大系统

350km的海底光缆传输系统，是采用拉曼放大还是采用远程激发光放大，文中详细论述和比较了这一问题，并介绍到：从接收端向光纤发射波长为1．48μm、功率为1w的激发光，由它来激发海底光放大器中的EDF，放大发送端传输的信号光，以确保系统稳定运行。     

光工作站的选择及使用

1引言光纤传输是通过光发射机将射频电视信号变换为红外波段的电磁波,即红外线光,使其沿光导纤维传输,到接收端再通过光接收机把红外波段的光转换为射频电视信号。光纤传输具有频带宽、损耗低、抗干     

光纤通信用受光元件

光纤通信与以往的通信方式相比具有频带宽,衰耗低,无电磁感应等优点,因而正在逐步走向实用。作为光纤通信的组成部件是由发射端将电转换成光的光源,传输光的光纤,以及在接收端将光转换成电的受光元件组成。 本文就对这种光纤通信中的受光器件加以论述。     

Undersea fiber cable technology

Compared with the conventional coaxial undersea cable systems, an optical fiber undersea cable system has a great technical and economical advantage. It is also suitable for digital transmission. In this paper, the optical fiber undersea cable technology (including optical fiber cables and repeaters), which is now in the research and development stage in several countries, is reviewed.     

有线电视传输系统常见故障维修

随着技术的不断发展,有线电视网络已从同轴电缆向光纤、模拟信号向数字信号、单向传输向双向传输转变,甚至向全光信号的方向发展。但因技术尚未完全成熟,其仍旧存在传输系统故障问题,相关人员应提高对其的重视程度。文中深入分析了有线电视双向网络传输的特点,对有线电视传输系统常见故障及维修方法进行了探究,并对屏幕横条、断线、终端无法注册、互动点播进入慢和同一局端下网速不稳定等故障进行了研究,以期为技术应用和有线电视传输系统的安全工作提供借鉴。     

Recent advances in submarine optical fiber cable transmission systems in Japan

Submarine optical fiber cable transmission systems are promising successors to existing submarine coaxial cable systems. This paper will review the history and the state of the art of the submarine optical fiber cable transmission technology, and the submarine optical fiber cable transmission systems named FS-400M and OS-280M being developed by NTT and KDD, respectively, in Japan.     

Present status and outlook of line transmission systems in China

The various line transmission media, including open wires, symmetrical pair cables, coaxial cables, and optical fiber cable, that are used in the different regions of China are described. Both analog transmission systems and the newer digital transmission systems are discussed. The standardized physical transmission media deployed throughout China-symmetrical pair cables, coaxial cables, and optical fiber cables-are also discussed     

Optical Fiber System Applications Aspects in Future NTT Networks

This paper describes some aspects of optical fiber cable system applications in future NTT transmission networks, considering voice transmission as predominant even in future transmission networks in accordance with demand forecasts. The desirable optical fiber cable transmission system which should be developed and introduced is discussed taking into account optical fiber costs, demand estimates, pertinent technological developments, etc. It was concluded that the following process of introducing optical fiber cable transmission systems should be feasible. In the first step, approximately 32 Mbit/s and 100 Mbit/s digital transmission systems should be employed for short and medium haul trunks with heavy traffic using graded index optical fibers. A large capacity, long haul digital transmission system, such as a 400 Mbit/s system using graded index or, if possible, single mode optical fiber should be introduced next. The optical fiber cable costs at which fiber systems become economical, depend upon the application area. For short and medium haul systems, 40¢ per meter per core is required, but $2 per meter per core is sufficient for large capacity, long haul systems. For a short haul system operating at approximately 1.5 Mbits/s or 6 Mbits/s, the advantages of its introduction greatly depend on optical fiber costs which should be less than 20¢per meter per core.     

试论有线传输的技术特点和发展方向

在信息时代背景下,信息传输系统日臻完善,信号传输介质也不断优化与更新。相较于无线传输技术而言,有线传输的稳定性更佳、信号传送速度更快,能够实现信号的高质量传输。由于采用不同介质的有线传输技术特征不一,因而文章将对双绞线电缆、架空明线、同轴电缆、光纤四种不同有线传输技术的特征展开逐一探讨,而后对有线传输技术的未来发展方向做出预判。     

基于CPLD的汇聚视频光端机的设计与实现

针对传统的视频传输方案容易造成视频线或者光纤的浪费,利用复杂可编程逻辑器件CPLD、串并转换芯片和并串转换芯片及九针光模块和SFP光模块,通过时分复用技术,设计一个专用的光纤传输系统,仅需要少量光纤和少量视频线就可以完成视频传输。     

基于DWDM技术的光纤CATV

作为一种理想的传输媒质，光纤正在代替CATV原来使用的同轴电缆，光纤CATV已成为国内广播电视行业的发展趋势，DWDM技；卡使CATV网络中已敷设的光纤获得充分利用，这一技术在光纤CATV中正越来越多地得到使用。     

光纤CATV传输系统的结构和应用

光纤CATV传输系统包括光发射机、光接收机、光纤和必要的光通路器件（如光分路器、光纤连接器）等。该系统采用光纤／同轴电缆混合网（HFC）结构，是一种宽带、低成本的实现方式。结合实际开发工作，简要介绍了光发射机、光接收机及相关器件的工作原理。     

Research toward optical-fiber transmission systems

The fundementals of optical fiber transmission systems including the fiber transmission medium, sources suitable for use as a carrier, modulation and detection techniques, and some system design considerations are reviewed. The advent of low-loss optical fibers brings new dimensions to optical communication prospects. Fibers may soon be used much as wire pairs of coaxial cable are now used in communication systems. Transmission losses as low as 2 dB/km have been achieved. Experimental repeaters for fiber systems with 10^-9error rate at about 300-Mb/s pulse rate have been reported. Fiber cabling and splicing are among the problems requiring new ideas in order to make feasible an operable system.