INPUT CIRCUIT OF VHF TELEVISION SET TUNER

摘要

The present invention relates to an input circuit of a VHF of a television set tuner and includes first and second inductive elements connected in series with each other and in parallel with a varactor, forming a resonance circuit with the varactor for selecting a desired lower channel from an incoming television signal. The second inductive element has at least one tap connected to the following stage for transmitting signals of the desired lower channel. A third inductive element is connected to a junction of the first and the second inductive elements and connected in series with the first inductive element and forming therewith a parallel resonance circuit with the varactor for selecting a desired higher channel from the incoming television signal. A first switching circuit is interposed between the junction and the following stage and being operable to conduct for transmitting the desired higher channel therethrough to the following stage. A capacitor is connected in series with the third inductive element and forming a wave trap therewith. A second switching circuit is interposed between the junction and the wave trap and being rendered conductive when receiving the desired higher channel for passing the same, and the first and the second switching circuits being rendered non-conduc-tive when receiving the desired lower channel.