To make it possible to reduce the cost and judge the correctness by making a digital signal processing circuit into a single system.
The output signal of the digital signal processing circuit 4, to which known A system and B system check signals C(A) and C(B) are added, becomes a prescribed output signal corresponding to the types of the signals C(A) and C(B) when the circuit 4 is normal. A judgement signal with effect that the circuit 4 is normal is outputted from a check circuit 5 and the output signal of the circuit 4 is used for the other unit control signal. When the circuit 4 is abnormal, the signal does not become the prescribed signal corresponding to the type of the signal C(A) and C(B) and the judgment signal with effect that the circuit 4 is abnormal is outputted from the circuit 5. The output signal of the circuit 4 is not used for controlling the other unit. The correctness of a device can be judged without constituting the circuit 4 by a multiplex system and cost can be reduced.
TAKANO TOSHIO
SAITO YASUO
Next Patent: BIT SYNCHRONIZATION CIRCUIT