Patent ID: 9261453
Filing Date: 2016-02-16
CPC Classification: G01J,G01N

Claim Text:
1. A method for measuring concentration of a gas component in a sample gas via a gas analyzer, the method comprising: varying a wavelength of light of a wavelength-tunable light source in periodically successive sampling intervals and, during which, sinusoidal modulation with a modulation frequency is also implemented to perform wavelength-dependent sampling of an absorption line of interest of the gas component; guiding modulated light through the sample gas to a detector, demodulating a measurement signal generated by the detector at a second harmonic of the modulation frequency; evaluating an obtained demodulated measurement signal to form a measurement result for each sampling interval; additionally modulating the wavelength of the light of the light source with at least one further frequency which is greater than a next lowest further frequency or the modulation frequency by twice a magnitude of the modulation frequency; additionally demodulating the measurement signal at the second harmonic of the at least one further frequency; and combining at least one further obtained demodulated measurement signal with the demodulated measurement signal or evaluating the at least one further obtained demodulated measurement signal to form a further measurement result which is combined with the measurement result.