| 摘要 |
<p>PURPOSE:To obtain a group of counters whose updating time is completely the same by mutually transferring a synchronizing signal synchronized by a synchronizing circuit between its own system and the other system, and selecting and outputting a signal outputted first out of synchronizing signals from the self-system and the other system as a synchronizing signal for updating a TOD counter. CONSTITUTION:Both the systems are respectively provided with synchronizing circuits 12, 22 to be driven by a common clock 1, and time-of-day (DOD) count signal forming circuits 10, 20 which synchronizes synchronizing signals with nearly constant period sent from the other and its own systems and generates a synchronizing signal, are respectively provided with synchronizing signal sending circuits. The synchronizing signal sending circuits mutually send synchronized synchronizing signals and each of them selects and outputs a synchronized signal output first out of the synchronizing signals in the its own system and the other system as the updating signal of the TOD counter and updates the TOD counter by the updating signal. Consequently, even when a circuit has plural synchronizing circuits, their updating time can be allowed to coincide and all TOD values can always be allowed to coincide with each other.</p> |
