| 摘要 |
PURPOSE:To diagnose a pulse measuring circuit without using standad IC, by providing a means which inputs a reference pulse to the pulse measuring circuit as a pulse to be measured and another means which decides the normality of a measured result, etc. CONSTITUTION:A basic clock CLK sent by a pulse oscillator 16 is divided in frequency 22 and three kinds of reference pulses RP1-RP3 having different frequencies are produced. Then a multiplexer 20 is controlled by a control section 21 and one of the reference pulses RP1-RP3 is selected. The pulse width of the selected reference pulse is measured and inputted to a digital comparator circuit 24. On the other hand, reference value data corresponding to the selected reference pulse are previously inputted to the comparator circuit 24. When the difference between the reference value and measured value is within a permissible range, it is decided that a pulse measuring circuit 12 operates normally at least on the currently selected reference pulse and a normality decided report is sent to the control section 21 from the comparator circuit 24. When the difference is out of the range, an abnormality decided report is sent to the control section 21.
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