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…     

影响有线电视网络光链路指标的综合因素

在有线电视光缆干线系统中，影响C／N，CSO，CTB等主要技术指标有多种因素。以1310nm光纤传输系统为例分析了各种因素对光链路指标的影响。     

有线电视光链路的设计及计算方法

由于光纤传输有频带宽、损耗低、抗干扰能力强、保真度高、工作性能可靠等优点,加上近年来光缆价格不断下降,因此光缆在有线电视及增值业务中的应用越来越普及,尤其是镇乡一级广电站的干线,大有光缆替代电缆之势,但是在光缆的链路设计和计算方     

有线电视光分配网链路设计浅谈

我国NGB与三网融合建设已进入了实施阶段,“光进铜退”是世界宽带接入网共同发展道路,也必然是中国NGB有线接入网的发展道路.模拟电视光链路和野外光节点的应用场景,已不适合数字电视传输和FTTx(光纤到楼、光纤到户)的应用需要,广电运营商进行有线电视网络双向化改造也是发展的必然趋势.在双向化网络设计中,如何科学、准确的计算光链路性能指标在光网络设计中显得尤为重要.本文就结合我县实际,深入探讨光链路性能指标计算的方式方法,为设备选型提供科学依据,为网络设计提供理论基础.     

有线电视光链路技术维护浅析

近年来随着有线广播电视事业的飞速发展,全国地市级以上有线电视都先后完成了有线电视光缆网络升级改造。商丘有线广播电视光缆传输网总体规划为双向860MHz系统,城区网络设计为1310系统,市区到六县一市远距离网络设计为1550系统。城域网区设睢阳、农行、道北分前端,采用“环-星-树”型光缆拓扑结构,充分体现冗余备份,提高网络运行的可行性,即在城区的一级主干网上采用环型网络拓扑结构,在支干网络上采用大量型加小环型拓扑结构通过环网上的主节点(主前端、分前端)。经支干线网呈全星型拓扑到光节点,城区已建设光节点300个,每个光节点所带用…     

发展乡镇有线电视的几点建议

分析了乡镇有线电视目前面临的危机和存在的问题,提出了解决问题的方法和发展乡镇有线电视的几项建议.     

发展乡镇有线电视的几点建议

分析了乡镇有线电视目前面临的危机和存在的问题，提出了解决问题的方法和发展乡镇有线电视的几项建议。     

CATV光链路的分析与计算

有线电视系统中的长距离传输电缆必将被光缆代替，故本文对光传输原理，参数指标是行了系统的介绍。并结合具体实例对ＣＡＴＶ光链路进行了分析与计算，仅供大家参考。     

有线电视HFC中光链路日常维护与故障处理

主要介绍了有线电视HFC中光链路的日常维护、故障判断和典型故障的处理方法以及相关注意事项。     

The SILEX optical interorbit link experiment

The European Space Agency (ESA) has instigated an in-orbit demonstration project known as SILEX (semiconductor laser intersatellite link experiment) using a pre-operational link between the French SPOT-4 low earth orbit satellite and the ESA Advanced Relay and Technology Mission Satellite (ARTEMIS). Such an optical communication system brings some new and challenging requirements. In particular, the communication beam, which has a divergence of around 6 μrad, must achieve and maintain a very demanding pointing accuracy in the presence of both host satellite vibration and relative satellite motion. The authors provide an overview of the SILEX project and describe a novel pointing mechanism     

大丰市市-镇-村有线电视传输网的建设

大丰市有线电视经过10多年的发展,现在已全面建成了覆盖全市城乡的有线电视网络, 实现了市-镇-村光纤大联网.     

有线电视双向HFC网络上行信道噪声分析

以相关数学公式以及物理定律为依据,对有线电视双向HFC网络上行道噪声模型进行了理论推导,提出了解决噪声干扰的办法。     

一款应用于FTTH的CATV光接收机的设计

在分析国内外FTTH光接收机应用前景的基础上,设计并实现了一款应用于FTTH的CATV光接收机.在低动态接收、高灵敏度和成本方面有较大突破,光功率接收范围达到-8～0dBm,功耗降低到约3W,制造成本降低到300元左右,具有很好的实用价值.     

Impedance-matched optical link for C-band satellite applications

Optical transmitter and receiver modules with passive impedance-matching circuits have been designed, constructed, and tested. A direct current modulated InGaAs DFB laser, operating at 1.3 micron, and an InGaAs PIN photodiode were matched to 50 ohms with passive, mixed lumped and distributed element, matching circuits. A link-insertion loss of 21 dB with a 3 dB bandwidth of 900 MHz has been demonstrated. Through the use of higher-order matching circuits, link-insertion loss variations across the satellite downlink frequency band (3.6-4.2 GHz) have been kept below ±0.5 dB     

A practical optical modulator and link for antennas

This paper describes a practical application of a technique for coupling an antenna to a receiver using a passive fiber-optic link. This technique should avoid pickup and electromagnetic perturbations normally associated with the use of electrically conductive cables. Laser light (632.8 nm) is modulated at the antenna by an electrooptic lithium-tantalate crystal and is then transmitted with a fiber-optic cable to the receiver electronics. Using an avalanche photodiode, the amplitude modulated optical signal is converted to an electrical signal. The crystal is mounted directly on an antenna without amplifiers or other electrically powered components. Using a broad-band antenna with fields generated in an anechoic chamber and a standard TEM cell, the frequency response as measured dropped 3 dB per 1.0 GHz from 100 MHz to at least 2.0 GHz, with a signal-to-noise ratio of 5 dB with a 1.0-V/m field and a 1.0-kHz bandwidth. A dynamic range of at least 60 dB is shown.     

Analogue optical link for multichannel frequency-modulated television transmission

The performance of an analogue optical link for the transmission of multichannel frequency-modulated TV signals with small frequency deviations is measured. A signal/noise ratio of 47 dB is achieved on a four-channel PAL system with a frequency deviation of 600 kHz, a bandwidth of 16 MHz per channel and an interchannel spacing of 18 MHz.     

Double crucible optical fibre for data link applications

A short distance, data link fibre has been made by the double crucible method. The fibre has a large core (175 ?m), high NA (0.4) and a minimum loss of 7.5 dB/km. By lowering the water content of the fibre the usable wavelength range has been extended to 1.3 ?m