| 摘要 |
PURPOSE:To eliminate the need to switch a redundancy system by an operator, to simplify the constitution, and to eliminate the possibility that a wrong system is selected. CONSTITUTION:As the device is powered ON, power-ON resetting circuits 31 and 41 output low-level signals for a certain time. The output low-level signal of the circuit 41 is supplied to selectors 342 and 343. The signal D of the circuit 31 is supplied to the selectors 342 and 343, so the selector 342 outputs a low level and the selector 343 outputs a high level. Consequently, a select signal generating circuit 35 outputs a high-level signal A and supplies it to a latch 451. At this time, the signal C is supplied to the hold input of the latch 451 while held at the high level, so the high level of the D input is outputted and supplied to an OR circuit 43 and a selector 46. The selector 46 selects and outputs a 0-system clock. |
