论文部分内容阅读
随着我国电视技术的发展有线电视已进入千家万户。有线电视信号通过光缆传送,传真度高、图像清晰、节目丰富多彩、抗干扰性好、可靠性高,是寻常无线射频发收方式所无法媲美的。本文介绍一种黑白电视机入网收视有线电视节目的简便方法。一般的VHF/UHF全频道黑白电视机,多采用VHF(甚高频)和UHF(特高频)分体式的机械式调谐器。VHF与UHF两种调谐器的输入特性阻抗不同,VHF调谐器的阻抗多为75Ω,而UHF调谐器的阻抗则多为300Ω。为此,黑白电视机后背往往备有VHF和UHF两路独立的端子接口,分别配合相应阻抗的电缆线与两副接收天线相联。有线电视用户
With the development of China’s television technology, cable has entered millions of households. Cable television signals transmitted through the cable, high fidelity, clear images, rich and colorful programs, good anti-interference, high reliability, is the way ordinary wireless RF transceiver can not be comparable. This article describes a simple way to view black-and-white television networks for viewing cable programming. General VHF / UHF all-channel black and white TV, the use of VHF (UHF) and UHF (UHF) split mechanical tuner. The input impedance of VHF and UHF tuners is different, the impedance of VHF tuner is 75Ω, and that of UHF tuner is 300Ω. To this end, black and white TV back often with VHF and UHF two independent terminal interface, respectively, with the corresponding impedance of the cable and the two receiving antenna associated. Cable TV users