调谐器是电视机的主要部件之一,其结构比较复杂,成本较高,而且也容易出现故障,因为它是一个机械-电子结合在一起的部件,而且对机械精度的要求较高。起初,甚高频(VHF)调谐器大都采用滚筒或波段开关的间断调谐,以后改用按键开关的L和C连续调谐。这样,虽则在可靠性或造型方面有所改善,但未能摆脱机械元件的影响。超高频(UHF)调谐器的发展亦是如此。多年来,在使调谐器摆脱机械元件方面作了许多努力,取得了可喜的成绩。调谐用变容二极管来代替可变电容器;频道切换用 The tuner is one of the main components of a television. The structure of the tuner is complicated, expensive and prone to failure because it is a mechanically and electronically integrated component that requires high mechanical precision. Initially VHF tuner mostly used intermittent tuning of the drum or band switch, later switched to L and C continuous tuning of the key switch. In this way, although the reliability or styling has been improved, but failed to get rid of the mechanical components. The same goes for the development of UHF tuners. Over the years, many efforts have been made to free the tuner from mechanical components and have achieved gratifying results. Tuning with varactor instead of variable capacitor; Channel switching