The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 15, 1999
Filed:
Oct. 20, 1997
Orbisphere Laboratories Neuchatel S.A., Neuchatel, CH;
Abstract
A method and apparatus for determining the concentration of a substance of interest by gas-coupled photoacoustic spectroscopy (GC-PAS) with an essentially monochromatic beam of radiation in an optical portion of the electromagnetic spectrum; the radiation is selected so as to be absorbed by the substance of interest and the beam is modulated at a sonic frequency which is sufficiently high for generating a primary signal that depends upon the absorption coefficient of the substance of interest as well as upon parameters of operating the method; in order to compensate for these operating parameters, the beam is additionally modulated at a sonic frequency which is sufficiently low for generating a secondary signal which does not depend upon the absorption coefficient of the substance of interest, but, depends only upon parameters of operating the method; a ratio of the first and the second signal is obtained to generate a compensated signal for determining the concentration of the substance of interest.