职中电子专业同学不一定都学习了彩电,有的仅仅在《电视机原理及电路分析》中粗略地学习了电子调谐器原理。这对彩电难点之一的电子调谐器和预选器原理自学会有很大困难,尤其是预选器原理,现作简要介绍,想必对同学们有所裨益。彩电预选方法如下表所示。预选方式{非遥控式——非遥控彩电用,遥控式[电压合成式,PLL频率合成式——少用,(半自动搜索选台,全自动搜索选台)]}正在多用 E-matriculation students are not necessarily all learning color TV, and some simply in the “principle of the TV and circuit analysis,” a rough study of the electronic tuner principle. This is one of the difficulties of color TV tuner and preselector principle of self-learning will have great difficulty, especially the principle of preselector, now a brief introduction, presumably beneficial to the students. TV pre-election method as shown in the following table. Preselection method {non-remote control - remote control color TV, remote control [voltage synthesis, PLL frequency synthesis - less, (semi-automatic search station, automatic search station)]}