| 摘要 |
<p>A device able to detect gas in the atmosphere, based on a IAFOS (Infrared Absorption Fibre-Optics Spectrometer) composed of a central unit (1) connected to at least one measuring cell (2) by one or more optical fibres (3); the central unit (1) contains a stabilized laser source (4) operating at wavelengths above 2,9 microns and modulated with a wavelength frequency F ranging from 500 Hz to 200 KHz; the central unit also includes a lock-in amplifier (20) operating at a frequency 2F, receiving as an input the detected return signal from the measuring cell (2); the output signal I2F is then processed in the processing unit (12) in order to detect gas in the atmosphere. <IMAGE></p> |
