Abstract: A method for analyzing a gaseous medium with respect to a component having a characteristic absorption frequency spectral line, including the steps of generating microwave radiation at a selected frequency, generating a first Stark voltage selected to have a value such that a reference signal produced by subjecting the component to the microwave radiation and the first Stark voltage has a zero passage, resulting from the change in polarity between the spectral line and the Stark voltage lines, at a frequency coinciding with the characteristic absorption frequency spectral line, and regulating the microwave radiation frequency as a function of frequency shifts of the zero passage of the reference signal.

Abstract: A method and appparatus for continuously measuring the concentration of at least one component of a gas sample by means of a laser for the purpose of charging the gas sample with radiation at a frequency in the range of an absorption line of the component, and employing a detector device for receiving a measurement signal corresponding to the intensity of the transmitted radiation and an evaluation circuit. A single mode laser is employed which is linearly tuned about a gas specific absorption line by means of bandwidth modulation so that at least two different intensity measurement values are obtained for the transmitted radiation from which the extinction, and thus the concentration of the gas component, is determined.