Research of oxygen concentration information detecting method with LIA

摘要

A method of detecting weak signals by two lock-in amplifiers is introduced to detect oxygen concentration as a weak signal, in the process of detecting oxygen concentration based on TDLAS. In this paper, the working principle of lock-in amplifier is described, and the principle and characteristics of detecting weak signals with two lock-in amplifiers are analyzed. The second harmonic signal is selected as the main extraction target. By simulating and analyzing the extraction process of signal with different phase, the feasibility and importance in improving detection accuracy are verified.