| 摘要 |
PURPOSE:To display pictures of plural channels simultaneously with a small number of channel selection switches, by depressing the switch of an arbitrary channel to generate plural control signals having different numbers of pulses from the controller. CONSTITUTION:Reset output Reset and channel up outputs CHU1-CHU4 are output when 1ch of channel selection switch 23 is closed. In this case, though the reset signal is input to channel selecting circuit 13, signal CHU1 has no pulses, and the first position is selected. The reset signal and signals CHU2-CHU4 are input to channel selecting circuits 14-16 respectively, and signals CHU2, CHU3, and CHU4 have one, two, and three pulses respectively, and the 2nd-the 4th positions are selected respectively. Circuit 13 selects the same positions as channel selection keys even if channel selection keys 2-12ch are closed, and circuits 14-16 select large positions respectively. Consequently, four channel selecting circuits are selected with only one set of the channel selection switch. |
