| 摘要 |
<p>PURPOSE:To enable self diagnosis of abnormality based on measurement results by calculating apparent probabilities of generation of Stokes light and anti- Stokes light at one or more sampling points from the measurement results of a physical quantity distribution along an optical fiber to determine a difference between both the probabilities. CONSTITUTION:Back scattering light intensity distributions Gs (x) and Ga (x) are measured at wavelengths of Stokes and anti-Stokes lights at a sampling distance (x) in an optical fiber 4. Apparent probabilities Rs (x) and Ra (x) of Stokes and anti-Stokes lights as generated at a point (x) are calculated. A difference of probabilities Rs (x) and Ra (x) is determined and when the difference is off a fixed range, abnormality that may make the measurement result uncertain is determined to occur. Receiving outputs of a temperature measuring device 42 provided in an abnormal diagnosis circuit 11, equalization processing circuits 7a and 7s and a specified area 41 as input, an abnormality diagnosis circuit 11 determined abnormality judging from above-mentioned calculation results and a display to the effect of abnormality is made in a temperature distribution display device 10.</p> |
