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1 项目背景1.1 某单位有线电视系统的历史沿革与现状 某单位有线电视系统始建于1985年,至今已有19年的历史。现有用户1750户,分布于10个小区,距总前端最远的距离为7km。 2003年初,本系统建设并开通了数字有线电视前端(DVB-C),实现了模拟与数字信号混合播出,其中数字节目为116套,模拟节目为50套。因此,从节目数量和质量上以及技术设备上均属于国内领先并达到了国际先进水平。但是,由于多数小区的电视网建设时间较早,分配网大多已不符合现行国标或部标,如采用树型分支拓扑结构,甚至还有串接单元方式;加之有些小区电缆老化、元器件大都是早期落后甚至是应该淘汰的产品,其性能指标达不到现行技术标准。
1 Project Background 1.1 The history of a unit of cable television system and the status quo A unit of cable television system was founded in 1985, has been 19 years of history. 1750 existing users, located in 10 residential areas, the total distance from the front end of the 7km. In early 2003, the system built and opened up the digital cable television front end (DVB-C), which realized the mixed broadcasting of analog and digital signals, including 116 digital programs and 50 analog programs. Therefore, from the number of programs and quality and technical equipment are the leading domestic and reached the international advanced level. However, most of the district’s TV network construction time is earlier, most of the distribution network does not meet the current national standard or departmental standard, such as the use of tree branch topology, or even a series of cell units; combined with some of the district cable aging, most of the components Is outdated or even should be eliminated products, its performance indicators do not meet the current technical standards.