| 摘要 |
PURPOSE:To perform an on-line decision on the fault of an amplifying means independently of the level of an original digital signal by superposing pulses for fault diagnosis upon the original digital signal and supplying them to an EOR circuit, and comparing the input and output signals of the amplifying means with each other. CONSTITUTION:A pulse generating circuit 10 divides the frequency of sampling pulses 19 and outputs the pulses 17 for diagnosis. The EOR circuit 11 inputs the original digital signal 7 and pulses 17 and outputs their superposition signal to a transistor (TR) 3. A NOT circuit 6, on the other hand, reinverts the digital amplified signal 8 obtained by inverting and amplifying the signal 15 through the TR 3 and outputs a feedback signal 9 of the same level with the signal 15. An EOR circuit 12 inputs the signals 15 and 9 to supply a latch circuit 14 with a comparison signal 16 of 'H' when both signals differ in level or 'L' when equal. The circuit 14 supplies the latched diagnostic output signal 20 to a computer. Therefore, the circuit 12 and 14 compares the levels of the signals 15 and 19 with each other at a high speed.
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