| 摘要 |
PURPOSE:To prevent a signal value from being changed by attaching another digital circuit on an analog processor device, and holding an output signal without drifting for a long time when a fault is generated in the operation of the processor. CONSTITUTION:When the operation of a microprocessor 1 is performed normally, a digital signal following the output signal Vout of a signal holding circuit 2 at every constant cycle is held at a counter 4 by a loop consisting of a counter 4, a D/A converter 5, a comparator 6, and a logic circuit 7. When abnormality is generated in the operation of the processor 1 at such state, the fact is detected by a monitoring means 3, and a switch SW1 is operated, then, the processor 1 is separated. In other words, a gate control circuit 73 in the circuit 7 receives a signal from the means 3, and cancels the above loop, and simultaneously, turns on the switch SW1 until malfunction in a synchronous circuit 74 is eliminated. Next, when the fault is eliminated, the digital signal without having the fault just before held at the counter 4 is inputted to the signal holding circuit 2 via the converter 5, and the output signal Vout is sent out from the circuit. |
