| 摘要 |
The present invention realizes a small-size and inexpensive television tuner's intermediate frequency tuning circuit that can be used for both television intermediate frequency signals and FM broadcast signals frequency-converted to 10.7 MHz. The television tuner's intermediate frequency tuning circuit comprises: a parallel tuning circuit (4) to both ends of which a television intermediate frequency signal or an FM broadcast signal frequency signal or an FM broadcast signal frequency-converted to 10.7 MHz is inputted; a series tuning circuit (5) connected in parallel to the parallel tuning circuit; and switch means (8), connected in parallel to a capacitive element (4b) of the series turning circuit, that is closed when the intermediate frequency signal is inputted, and opened when the FM broadcast signal is inputted, wherein the respective tuning frequencies of the parallel tuning circuit and the series tuning circuit are set to 10.7 MHz or more; when the switch means is closed, a parallel tuning frequency produced by the parallel tuning circuit and the series tuning circuit is set to the frequency of the intermediate frequency signal; and when the switch means is opened, the parallel turning frequency is set to 10.7 MHz. <IMAGE> |
