| 摘要 |
PURPOSE:To make unnecessary the inspection of respective reference circuit of the inspection unit, by using the reference logic circuit expressing the logic functions of the inspected logic circuit with equivalent state transition function and output function. CONSTITUTION:The inspection input signal X is fed to the inspected logic circuit 2 and the reference logic circuit 3 at the same time. The circuit 2 outputs the signal Z' as the response to the signal X. On the other hand, the reference logic circuit 3 memorizes the state transition function and output function representing the logic function equivalent as the circuit 2, performs the logic operation according to the state transition function memorized to the signal X, and as a result, the signal Z expected when the circuit 2 is normally operated in accordance with the output function is outputted. Next, the signals Z' and Z are compared with the propriety judging circuit 4, and if there is any difference, the failure detection signal is caused. Accordingly, by using the circuit 3, the inspection of the respective reference logic circuit can be made unnecessary. |
