摘要
为了提取淹没在噪声中的弱吸收信号,对波长调制光谱测量中的相敏检测技术进行研究,提出了一种数字化相敏检测实现方案。采用正交矢量型结构实现相敏检测过程,通过硬件电路设计和上位机程序编写,完成吸收信号谐波分量的获取。对空气中的O2进行检测,针对O2位于764nm附近的一对吸收谱线,成功提取了吸收信号的二次谐波分量。结果显示,系统的检测极限体积分数为0.50%(光程为1m)。
In order to detect weak absorption signal overwhelmed in noise, phase-sensitive detection technique used in wavelength modulation spectroscopy system is studied, and a design scheme for digital phase-sensitive detection is presented. An algorithm of orthogonal vector structure is analyzed, and then the extraction of harmonic component is realized by hardware circuit design and computer software programming. The experiment is carried out for the measurement of 02 in open air by scanning two absorption lines of 02 near 764 nm, and the second-harmonic signal is successfully extracted. The result shows that the detection limit for volume fraction of the system is 0.50% （with the optical path of 1 m）.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2013年第11期251-256,共6页
Chinese Journal of Lasers
基金
国家自然科学基金青年科学基金项目(61205151)
国家自然科学基金(61108034)
中国科学院先导专项(XDA05040102)
关键词
光谱学
信号处理
可调谐半导体激光吸收光谱
波长调制
相敏检测
二次谐波信号
spectroscopy
signal processing
tunable diode laser absorption spectroscopy
wavelength modulation
phase-sensitive detection
second-harmonic signal
