| 摘要 |
PURPOSE:To hold the contents of a counter memory for a long period of time since a power supply is turned off without increasing a recording/reproducing device in scale by adding a circuit which detects that the contents of the counter memory are faulty. CONSTITUTION:The up/down counters 1-4 of 1-4 digits apply a binary coded decimal system and therefore and outputs showing the states of numeric characters 10-15, i.e., 1010, 1011, 1100, 1101, 1110 and 1111 of binary notation are not outputted in a normal state. If a power supply is switched off and the counters 1-4 shows either one of said states, this fact is detected by a discriminating circuit consisting of gates 5 and 9, 6 and 10, 7 and 11 and 8 and 12 respectively. Then the output of a gate 13 is set at 1 as soon as the power supply is switched on next time. Thus the counters 1-4 are cleared via a clearing circuit consisting of gates 15 and 16. On the contrary, the counters 1-4 are never cleared even though the power supply is switched on next time as long as a manual switch 17 is closed, in case the counters 1-4 are not showing any one of above-mentioned states. |
