Spectroscopy and Spectral Analysis, Volume. 33, Issue 4, 881(2013)
Simulation and Analysis of Second-Harmonic Signal Based on Tunable Diode Laser Absorption Spectroscopy
Tunable diode laser absorption spectroscopy (TDLAS) is a new gas detection technique developed recently with high spectral resolution, high sensitivity and fast time response. The second-harmonic signal of wavelength modulation spectroscopy (WMS) is often used as the detection signal for gas concentration inversion. Using Simulink, a visual modeling and simulation platform, the authors simulated the WMS signal based on TDLAS, and got the second-harmonic signal by using lock-in amplifier algorithm. Digital orthogonal algorithm was studied in this paper. The relationship between second-harmonic signals and the modulation indexes was analyzed by comparing changes of second-harmonic under different modulation indexes, in order to find out the optimized parameters for second-harmonic detection.
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LI Han, LIU Jian-guo, HE Ya-bai, HE Jun-feng, YAO Lu, XU Zhen-yu, CHEN Jiu-ying, YUAN Song, KAN Rui-feng. Simulation and Analysis of Second-Harmonic Signal Based on Tunable Diode Laser Absorption Spectroscopy[J]. Spectroscopy and Spectral Analysis, 2013, 33(4): 881
Received: Jul. 18, 2012
Accepted: --
Published Online: Apr. 8, 2013
The Author Email: Han LI (hanli@aiofm.ac.cn)