| 摘要 |
<p>PURPOSE:To allow measurement with high accuracy by providing a means for storing the position of an optical chopper and the relation thereof and sampling only the peak signal part. CONSTITUTION:The IR light of a light source 7 is intermitted at specified time intervals by the optical chopper 6 which is rotationally driven at a specified speed by a motor 8. These light rays are alternately introduced into a sample cell 1 and a referecne cell 2 and the respective transmitted light rays are admitted into a single detector 10. The detector 10 has chambers 10-1, 10-2 and the pressure difference corresponding to the difference in light absorption in the two chambers is detected by a pressure difference detecting element 11. The signal from the detector 10 is amplified 12, is subjected to A/D conversion 13 and is read by a microprocessor 14. The discrimination of the respective detected 10 peak signals on the cell 1, 2 sides and the timing of sampling are controlled with lapse of time with the rise of the signal of a photosensor 5 which detects the position of a chopper 6 as a start point.</p> |
