| 摘要 |
<p>PURPOSE:To reduce interference and influences due to disturbing components, when light from a light source is divided and alternately introduced into a correlation cell and a compensation cell, by providing a light reducing plate at the side of the compensation cell to adjust the ratio between light quantities to both the cells. CONSTITUTION:Light emitted from a light source 1 is divided by a divider 2 and alternately introduced into a correlation cell 4 and a compensation cell 5 by a chopper 3. A light reducing fixed plate 9 or the like is provided to extend across the optical path for the compensation cell 5 to adjust the ratio of light quaitites to both the cells 4, 5. As a result, the signal ratio between light outputs IR, IS from the cells 4, 5 is optically adjusted and the output are alternately passed through a sample cell 6 and received by a detector 8 through a filter 7. The detector 8 converts the each light output into an electrical current. This current is processed by a calculation circuit. According to this method, the influences of the contaimination of the cells, the deterioration of the light source, etc. are eliminated and measurement of NOX or CO concentration or the like can be accurately effected.</p> |
