Patent ID: 6091504
Filing Date: 2000-07-18
Classification: G01N

Abstract:
A gas analyzer for detecting the concentration of a gaseous component of a gas sample, comprising:a sample cell containing an unknown concentration of said gaseous component;a driving circuit which generates a laser driving signal;a laser light source which outputs laser light that is continuously varied through a range of frequencies including a characteristic absorption frequency of said gaseous component in response to said laser driving signal and that is not locked or tuned to said characteristic absorption frequency of said gaseous component, said continuously varying laser light being directed through said sample cell whereby laser light at said characteristic absorption frequency may be absorbed in proportion to the concentration of said gaseous component in said sample cell;a detector which detects laser light in said range of frequencies which has passed through said sample cell and which has been absorbed at the characteristic absorption frequency of said gaseous component to provide a detection output; anda compensation circuit which demodulates said detection output to remove said laser driving signal so as to leave an absorption signal with characteristic absorption lines at points in said absorption signal where said laser light source outputs light at said characteristic absorption frequency of said gaseous component, a magnitude of said characteristic absorption lines being proportional to the concentration of said gaseous component in said gas sample.