Open AccessA new method of background elimination and baseline correction for the first harmonic
Author(s) -
Rui Zhang,
XiaoFan Zhao,
Hu Ya-Jun,
Yuanyuan Guo,
Zhe Wang,
Ying Zhao,
Li Zhi-Xiao,
Yan Wang
Publication year - 2014
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.63.070702
Subject(s) - signal (programming language) , tunable diode laser absorption spectroscopy , optics , laser , noise (video) , harmonic , absorption (acoustics) , distortion (music) , materials science , physics , tunable laser , computer science , acoustics , optoelectronics , amplifier , cmos , artificial intelligence , image (mathematics) , programming language
A new method of background elimination and baseline correction is proposed, since there are background signal and larger baseline signal in the first harmonic (1f) of the tunable diode laser absorption spectroscopy (TDLAS). The laser-associated intensity modulation signal, electronic noise, and optical interference fringes of the 1f background are analyzed. Harmonic detection in none absorption spectral region (HDINASR) is used to eliminate the background signal. Then the relationship curve between current and intensity is given in different operating temperatures to design a remaining baseline correction method after eliminating the background. The principle of background signal searching and the LabView software flow chart are also given. The TDLAS experimental system is designed to detect hydrogen fluoride (HF) gas. According to spectral line selection principle, the absorption line -1312.59 nm is selected, whose operating temperature is set at 27.0 ℃ and the background temperature is set at 30.2 ℃. After eliminating the background and correcting the baseline, signal distortion is significantly improved and baseline is corrected. Then it is verified that the method is valid at other operating temperature of the laser (26.7-27.2). And the improvement of HF gas concentration is quantitatively analyzed. It is convenient for the subsequent processing of 1f signal.