论文部分内容阅读
近年来,共用天线电视系统的研制成功和推广运用,极大地改善了电视接收效果。但目前,许多棱乱的电视天线在建筑物顶上仍可看到,它不仅影响城市市容,而且使接收效果也不理想,又没有防雷措施,还威胁到电视机和人身安全。为此,很有必要迅速宣传和推广共用天线电视系统,改善电视接收效果。本文就这方面的基本知识予以介绍。共用天线电视系统可以因用户的多少、繁简程度而不同,它与接收地区的电视信号场强、楼房分散程度有关,还和需要接收和传递电视频道的数目有关。共用天线电视系统主要可分为三个部分,如图1所
In recent years, the successful development and promotion of the common antenna TV system has greatly improved the television reception effect. However, at present, many chaotic TV antennas are still visible on the roof of buildings. They not only affect the city’s appearance, but also make the reception unsatisfactory and have no lightning protection measures. They also threaten the TV and personal safety. For this reason, it is necessary to promptly publicize and promote the shared antenna television system to improve the television reception. This article describes the basic knowledge in this area. The common antenna TV system may vary depending on the number of users and the degree of complexity. It is related to the field strength of the television signal in the receiving area, the degree of building dispersion, and the number of television channels that need to be received and transmitted. Shared antenna TV system can be divided into three parts, as shown in Figure 1