| 摘要 |
PURPOSE:To prevent the returning of an ACK signal even when a selecting signal comes before a delaying element is returned by opening a selecting response signal ACK output gate since a delaying element output signal comes to be significant from the silence. CONSTITUTION:The Q output of a D-type flip-flop element 17 comes to be 'H' since a selecting signal is 'H' when no one is selected. In such a condition, access action is executed, a selecting signal comes to be 'L', then, the inverse of S input of the D-type flip-flop element 17 comes to be 'H', and at this time point, the Q output is still 'H' as it is. For such a reason, a G terminal of an inverter 3 with a gate is 'H' as it is and an ACK signal (d) is not returned. Next, when a delaying line 1 output signal (c) comes to be 'H' 'L' after a constant time Td, T input of the D-type flip-flop element comes to be 'L' 'H', the Q output comes to be 'L', the G input of a gate element 3 comes to be 'L', and the ACK signal (d) is returned to an access device.
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