| 摘要 |
PURPOSE:To hold a reception state stably automatically by allowing two tuners to receive broadcasts of the same contents differing in frequency, and selecting and outputting the larger detection output. CONSTITUTION:Tuners 3 and 4 receive signals of different frequencies from broadcasting stations which are arranged in respective different service areas like NHK (Japan Broadcasting Corporation) and deliver broadcasts of the same contents. The detection outputs S1 and S2 of the tuners 3 and 4 are sampled and held, and then converted into digital signals, which are compared with each other to check their identity. Even when the broadcasts are identical, the detection outputs S1 and S2 may have a slight time difference because their stations are different. For this purpose, sample holding is carried out with a slight time shift. When it is decided that the detection outputs S1 and S2 are identical, the broadcast with a higher level is selected by a switch 12 and outputted. |
