An optical fiber methane gas concentration detection method and system based on ramp wave modulation

Abstract

The invention discloses an optical fiber methane gas concentration detection method and system based on ramp wave modulation, which includes: using a ramp wave modulation signal as the driving current of a light source, respectively obtaining the relationship between the wavelength and intensity of the optical signal emitted by the light source and the modulation signal; According to Beer-Lambert's law, the light intensity signal after methane gas absorption is obtained; the light intensity signal is differentially processed to obtain the processed signal; the time point t1 and the light source wavelength at which the light source wavelength begins to enter the methane gas absorption line are judged The time point t2 is completely equal to the center wavelength of the absorption line; the differentiated signal is integrated from time t1 to time t2; the concentration of methane gas is obtained. The invention has beneficial effects: only wavelength modulation and differential demodulation are involved in signal algorithm analysis, avoiding the use of complex algorithms such as Fourier transform and harmonic analysis, saving signal processing time, and improving detection response speed.

Description

technical field [0001] The invention relates to the technical field of gas concentration detection, in particular to an optical fiber methane gas concentration detection method and system based on ramp wave modulation. Background technique [0002] Gas concentration detection methods include electrochemical methods, electrical methods, gas chromatography and optical methods. The electrochemical method uses electrochemical methods to detect gases using electrodes and electrolytes; the electrical method uses semiconductor gas sensitive devices for detection; gas chromatography is a physical separation analysis technology that uses adsorbents to make material components according to their adsorption capacity. Weak chromatography is a laboratory method in chromatography; optical method is to use the optical refractive index or spectral absorption characteristics of gas to detect gas. [0003] The optical fiber methane gas concentration detection method is an optical method base...

AI Technical Summary

Problems solved by technology

The method and system can not only solve the problem of detection error caused by random signals such as signal link coupling degree and environmental noise in the optical fiber methane gas concentration detection method that interferes with the light intensity, but also eliminate the impact of light source wavelength drift on detection. , further improving the detection accuracy

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