| 摘要 |
An instrument for determining the concentration of a particular gas that might be present in a sample has no moving parts and is extremely compact. The instrument uses as a source of radiation a device that has a radiating element whose temperature is alternated between T1 and T2 and whose spectrum approximates that of a blackbody. Radiation from this source is passed through a dual pass band filter that has two non-overlapping pass bands, one of which is centered at a wavelength at which the gas absorbs and the other of which is centered at a wavelength at which the sample does not absorb radiation. After passing through this filter, the radiation passes through the sample chamber and then is intercepted by a detector which produces an electrical signal determined by the radiation intercepted. The electrical signal is processed to provide an indication of the concentration of the gas.
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