| 摘要 |
PURPOSE:To eliminate large measuring errors, by providing a means for calculating a correlation between frequencies of a time counting pulse signal and a circuit operation pulse signal to detect any deviation when caused in the pulse frequency of an oscillator. CONSTITUTION:A value is calculated which is correlative to the frequencies of a time counting pulse signal and a circuit operation pulse signal and it is judged whether the value thus calculated is within a specified range or not. If no change is found in the frequencies of both pulse signals, the correlated value will be constant and also within a specified predetermined range. But when any abnormal deviation is fund in the frequency of any one pulse signal, the correlated value changes so much to be outside the specified range. If this happens, an error processing, for instance, an error display is done. For example, a CPU7 has a calibration curve table indicating correlations between received optical signals and sugar values in a built-in memory and has a function of reading a sugar value corresponding to a received light signal taken in, a function of checking abnormality in the frequency by determining both pulse signals of a system clock oscillator 13 and a timer oscillator 14, a function of processing errors in case of abnormality and the like.
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