| 摘要 |
PURPOSE:To enable the improvement of a photo loss measuring precision, by a method wherein, through the detection of an working temperature of a light source and light receiving element and the comparision of the result with a reference temperature, a flactuation in an output of a light receiving element, corresponding to a temperature change, is decided to compensate for temperature. CONSTITUTION:A substance 5 to be measured, such as photofibers, is placed between a light source 12 and a light receiving element 9 to measure the photo loss of the substance 5 to be measured. The working temperature of the light source 1 and the element 9 is high-precisely detected by high-sensitive thermisters 12a and 12b to compare it with a value corresponding to a reference temperature from a reference voltage generating circuit 11 by a comparator 16. A change in the output of the element 9, corresponding to a comparison output from the comparator 16 to apply the results to a reduction circuit 14. This causes the output of the element 9 to be highly precisely compensated for temperature, which results in the improvement of a photo loss measuring precision. |
