Balance detection circuit and detection method for directly measuring gas absorption spectrum shape

Abstract

The invention discloses a method for directly measuring the gas absorption spectrum shape, which belongs to the field of gas detection. In the method, two beams of light divided from one laser beam pass through two different light paths, then, two photodetectors are used for respectively detecting laser signals, and generated electric signals are amplified by a pre-amplification circuit, wherein one path of laser signals is absorbed by gas to be detected, and the other path of signals can be absorbed by gas with the known concentration or is not absorbed by gas. After passing through a divider, two paths of photodetector signals directly reflect the gas absorption intensity. If the signals also pass through a log device, the absorption factor can be directly obtained. The detection method of the invention directly eliminates the noise on the circuit before the data is collected, so signals collected by a subsequent data collection circuit directly form the proportional relationship with the gas absorption spectrum. The data processing process is simplified, the detection precision is improved, and in addition, the invention also discloses a balance detection circuit for directly measuring the gas absorption spectrum shape.

Description

technical field [0001] The invention relates to a gas measurement method, in particular to a balance detection circuit and a detection method for directly measuring the gas absorption spectrum shape. Background technique [0002] In atmospheric monitoring and various industrial process monitoring, the tunable laser absorption spectroscopy method has been paid more and more attention by utilizing the characteristics of different absorption wavelengths of different gases. This laser detection method using gas characteristic absorption lines has a series of advantages such as high sensitivity, strong selectivity, maintenance-free and long service life. It is an emerging gas detection technology that has developed rapidly in the past ten years. Its good technical development prospect has been paid more and more attention by researchers and users in related fields at home and abroad. Lasers stabilized by the characteristic absorption lines of gases can be used as standard wavele...

AI Technical Summary

Problems solved by technology

This modulated intensity is known as Residual Amplitude Noise (RAM), which severely limits measurement accuracy as the dominant background signal noise in harmonic detection methods

Moreover, the power-current output characteristics of the semiconductor laser itself often appear kinks, that is, nonlinearity, which will also become a kind of noise in detection

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