| 摘要 |
PROBLEM TO BE SOLVED: To provide an input circuit for a television tuner for allowing respective VHF and UHF tuning circuits to enhance their own intended characteristics by eliminating the mutual effect between the VHF and UHF tuning circuits. SOLUTION: The VHF tuning circuit 2 includes: two tuning inductance elements 2b, 2c connected in series with each other and the connecting point of which is coupled to an input terminal 1; and a first switch diode 2f connected entirely in parallel with the two inductive elements 2b, 2c, turned off when the input circuit is tuned at least to low frequencies of a VHF band and turned on when the input circuit is turned to high frequencies, and the UHF tuning circuit 9 is coupled to the input terminal via a second switch diode 7 turned on when receiving a television signal of at least the UHF band and the second switch diode 7 is turned off when receiving a television signal with low frequencies at the VHF band. COPYRIGHT: (C)2004,JPO
|
