二十年前的有线电视,多以电缆为主干进行长距离传输。典型的设计有远达二十公里的传输距离。现在由于光缆网络的迅速发展,以电缆远距离传输的网络业以消失,光缆网完全取代了电缆的主干传输地位。但是,现阶段要想做到光纤到户还有一定困难,最后一公里的传输应是以电缆网实现,对这最后一公里工程的优化,成为节约工程造价,提高传输质量 Twenty years ago, cable television was mostly based on the trunk cable for long distance transmission. The typical design has a transmission distance up to twenty kilometers. Now due to the rapid development of optical cable networks, the cable industry to the long-distance transmission of the industry to disappear, optical cable network completely replaced the backbone of cable transmission status. However, at this stage there is still some difficulty in achieving FTTH. The transmission of the last kilometer should be implemented by cable networks. The optimization of this last kilometer project has become a major task of saving construction cost and improving transmission quality