Method and measuring assembly for wavelength modulation spectroscopy

摘要

The method involves using laser light emitted by laser light source (2) into two beams (3,4) as analysis and reference laser beams. The analysis measurement detector (7) or reference measurement detector (9) are provided for detecting respective laser beams passing through to-be-analyzed gas (6). The noise caused by self-mixing effects of demodulated detector signal analysis is reduced by difference of demodulated output signals. The frequency modulated laser light is generated from light source based on nf signal analysis of detector, where n is a positive integer and f is frequency. An independent claim is included for measuring arrangement for performing wavelength modulation spectroscopy.