| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic tuning device for precisely and quickly presetting receiving frequencies of broadcasting channels. SOLUTION: A tuning control microcomputer 5 sets a specified frequency, and a detection circuit 3, a synchronization detecting circuit 4 and the microcomputer 5 detect whether a broadcast wave corresponding to the specified frequency should be received and carry out presetting. The presetting is carried out by detecting whether one channel should be received through a first frequency and a second frequency, and by determining one of the frequencies detected in the reception as a receiving frequency of the one channel. A center frequency of the one channel is tuned as the first frequency, and a low frequency, which is shifted to a low-frequency side with not less than 1/4 and not more than 2/5 of a frequency difference between the center frequency of the one channel and center frequencies of other adjacent channels existing in the same band, is tuned as the second frequency. COPYRIGHT: (C)2004,JPO |
