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:
Oct. 03, 2006
Filed:
Aug. 24, 2004
Rikard Larking, Floda, SE;
Stefan Lundqvist, Askim, SE;
Per-arne Thorsén, Öjersjö, SE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
In a wavelength modulation spectroscopy method and system the light of a tunable light source is modulated with a frequency f, while the wavelength is swept over an interaction feature of a sample to be measured. The light of the light source is passed to a sample for interacting and thereafter detected and demodulated at a higher harmonic Nf. To suppress effects of fluctuations of the optical transmission of the system on the measurement, originating from varying dust loads, high temperature, gas turbulence etc. in the measurement path (), a burst signal in form of an envelope modulated pilot tone is added to the modulation of the light () of the light source () synchronously with the wavelength sweeps at a wavelength outside the interaction feature of the sample. The injected burst signal is at the detection frequency Nf, where N≧, and is detected together with the measured spectrum from the sample and act as absorption normal, which the spectrum can be calibrated against.