| 摘要 |
<p>PURPOSE:To perform analysis with constant sensitivity by automatically correcting the change in the sensitivity of a detector even when said change due to the deterioration of the detector is generated, by providing light sources emitting infrared rays at different cycles to the light paths on both sides of a gas filter cell. CONSTITUTION:Light sources 8, 8' emitting infrared rays at different cycles are arranged on both sides of a gas filter cell 6 and the cycle of the light source 8 is made short while that of the light source 8' is made long to allow both light sources to light. Hereupon, the specific absorption band of infrared rays from the light source 8 is absorbed by the measuring component gas in the specimen gas introduced into a measuring cell 2 and the change in the quantity of light corresponding to the concn. of said gas is detected by a detector 12 to become a measuring signal. The specific absorption band of infrared rays from the light source 8' is almost absorbed by the measuring component gas sealed in the cell 6 and said infrared rays are received by the detector 12 without generating the change in the quantity of light to generate a comparing signal and the synthetic signal of the measuring signal and the comparing signal is outputted. This signal enters an AGC circuit 14 and the ratio of both signals when the level of the comparing signal is made constant is operated to calculate concn.</p> |
