| 摘要 |
PURPOSE:To attain efficient and stable pulse measurement by providing plural constant current circuits and selecting the constant current circuit in which the sensor signal level is over a specified level and the driving current is small. CONSTITUTION:Plural constant current circuits 15-17, in which constant current values are different, are provided as the constant current circuit for the LED9 of a pulse sensor 8. The amplitude level of the sensor signal of the pulse sensor 8 is stored in a level storing circuit 21 and this stored amplitude level is decided by a level deciding circuit 36. On the basis of a decided result, a switching control circuit 28 is controlled so that the constant current circuits 15-17, in which the sensor signal from the pulse sensor 8 goes over the constant amplitude level and the driving current is small, can be selected. |
