波长调制光谱测量系统中的数字化相敏检测实现
|
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 O2 in open air by scanning two absorption lines of O2 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).
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 O2 in open air by scanning two absorption lines of O2 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).
引文
1 D′Amato F,Lancia A,Werle P.Very precise measurement of carbon dioxide atmospheric concentration by using TDLs[C].SPIE,1996,2834:242-248.
2 Wang Guishi,Cai Tingdong,Wang Lei,et al..Application of digital frequency locking techniques in real-time measurement of methane in atmosphere[J].Chinese J Lasers,2011,38(10):1008002.王贵师,蔡廷栋,汪磊,等.基于数字频率锁定技术实时探测实际大气中甲烷浓度[J].中国激光,2011,38(10):1008002.
3 Zhang Zhirong,Dong Fengzhong,Wang Yu,et al..On-line monitoring of industrial toxic gases with a digital-control module[J].Acta Optica Sinica,2011,31(s1):s100304.张志荣,董凤忠,王煜,等.基于数字控制模块的工业有毒气体在线监测仪[J].光学学报,2011,31(s1):s100304.
4 XLiu,J B Jeffries,R K Hanson,et al..Development of a tunable diode laser sensor for measurements of gas turbine exhaust temperature[J].Appl Phy B,2006,82(3):469-478.
5 SSvanberg.Laser based diagnostics-from cultural heritage to human health[J].Appl Phys B,2008,92(3):351-358.
6 Kan Ruifeng,Liu Wenqing,Zhang Yujun,et al..Tunable diode laser absorption spectrometer monitors the ambient methane with high sensitivity[J].Chinese J Lasers,2005,32(9):1217-1220.阚瑞峰,刘文清,张玉钧,等.可调谐二极管激光吸收光谱法监测环境空气中甲烷的浓度变化[J].中国激光,2005,32(9):1217-1220.
7 Cui Houxin,Qi Rubin,Chen Wenliang,et al..Measurement of oxygen concentration using tunable diode laser absorption spectroscopy and wavelength modulation spectroscopy[J].Chinese J Lasers,2008,35(10):1558-1562.崔厚欣,齐汝宾,陈文亮,等.可调谐激光波长调制技术检测氧气浓度[J].中国激光,2008,35(10):1558-1562.
8 He Ying,Zhang Yujun,Zhu Anning,et al..Open-path ammonia high sensitivity on-line monitoring in farmland based on laser techniques[J].Acta Optica Sinica,2011,31(s1):s100407.何莹,张玉钧,朱安宁,等.开放式农田氨气的高灵敏激光在线监测[J].光学学报,2011,31(s1):s100407.
9 P Werle.A review of recent advances in semiconductor laser based gas monitors[J].Spectrochimica Acta Part A,1998,54(2):197-236.
10 JT C Liu,J B Jeffries,P K Hanson.Wavelength modulation absorption spectroscopy with 2fdetection using multiplexed diode lasers for rapid temperature measurements in gaseous flows[J].Appl Phys B,2004,78(3-4):503-511.
11 Liu Kun,Liu Tiegen,Jiang Junfeng,et al..Investigation of intra-cavity gas sensing technology based on wavelength modulation[J].Chinese J Lasers,2011,38(1):0105008.刘琨,刘铁根,江俊峰,等.基于波长调制技术的内腔式气体传感研究[J].中国激光,2011,38(1):0105008.
12 Gao Jinzhan.Detection of Weak Signals[M].Beijing:Tsinghua University Press,2004.154-170.高晋占.微弱信号检测[M].北京:清华大学出版社,2004.154-170.
13 Stutz Jochen,Platt U.Numerical analysis and estimation of the statistical error of differential optical absorption spectroscopy measurements with least-squares methods[J].Appl Opt,1996,35(30):6041-6053.
14 Tu Xinghua,Liu Wenqing,Wang Tiedong,et al..Noise analysis of second-harmonic detection with tunable diode laser absorption spectroscopy[J].Chinese J Quantum Electronics,2006,23(4):522 -526.涂兴华,刘文清,王铁栋,等.基于可调谐二极管激光吸收光谱学对二次谐波检测噪声分析研究[J].量子电子学报,2006,23(4):522-526.
2 Wang Guishi,Cai Tingdong,Wang Lei,et al..Application of digital frequency locking techniques in real-time measurement of methane in atmosphere[J].Chinese J Lasers,2011,38(10):1008002.王贵师,蔡廷栋,汪磊,等.基于数字频率锁定技术实时探测实际大气中甲烷浓度[J].中国激光,2011,38(10):1008002.
3 Zhang Zhirong,Dong Fengzhong,Wang Yu,et al..On-line monitoring of industrial toxic gases with a digital-control module[J].Acta Optica Sinica,2011,31(s1):s100304.张志荣,董凤忠,王煜,等.基于数字控制模块的工业有毒气体在线监测仪[J].光学学报,2011,31(s1):s100304.
4 XLiu,J B Jeffries,R K Hanson,et al..Development of a tunable diode laser sensor for measurements of gas turbine exhaust temperature[J].Appl Phy B,2006,82(3):469-478.
5 SSvanberg.Laser based diagnostics-from cultural heritage to human health[J].Appl Phys B,2008,92(3):351-358.
6 Kan Ruifeng,Liu Wenqing,Zhang Yujun,et al..Tunable diode laser absorption spectrometer monitors the ambient methane with high sensitivity[J].Chinese J Lasers,2005,32(9):1217-1220.阚瑞峰,刘文清,张玉钧,等.可调谐二极管激光吸收光谱法监测环境空气中甲烷的浓度变化[J].中国激光,2005,32(9):1217-1220.
7 Cui Houxin,Qi Rubin,Chen Wenliang,et al..Measurement of oxygen concentration using tunable diode laser absorption spectroscopy and wavelength modulation spectroscopy[J].Chinese J Lasers,2008,35(10):1558-1562.崔厚欣,齐汝宾,陈文亮,等.可调谐激光波长调制技术检测氧气浓度[J].中国激光,2008,35(10):1558-1562.
8 He Ying,Zhang Yujun,Zhu Anning,et al..Open-path ammonia high sensitivity on-line monitoring in farmland based on laser techniques[J].Acta Optica Sinica,2011,31(s1):s100407.何莹,张玉钧,朱安宁,等.开放式农田氨气的高灵敏激光在线监测[J].光学学报,2011,31(s1):s100407.
9 P Werle.A review of recent advances in semiconductor laser based gas monitors[J].Spectrochimica Acta Part A,1998,54(2):197-236.
10 JT C Liu,J B Jeffries,P K Hanson.Wavelength modulation absorption spectroscopy with 2fdetection using multiplexed diode lasers for rapid temperature measurements in gaseous flows[J].Appl Phys B,2004,78(3-4):503-511.
11 Liu Kun,Liu Tiegen,Jiang Junfeng,et al..Investigation of intra-cavity gas sensing technology based on wavelength modulation[J].Chinese J Lasers,2011,38(1):0105008.刘琨,刘铁根,江俊峰,等.基于波长调制技术的内腔式气体传感研究[J].中国激光,2011,38(1):0105008.
12 Gao Jinzhan.Detection of Weak Signals[M].Beijing:Tsinghua University Press,2004.154-170.高晋占.微弱信号检测[M].北京:清华大学出版社,2004.154-170.
13 Stutz Jochen,Platt U.Numerical analysis and estimation of the statistical error of differential optical absorption spectroscopy measurements with least-squares methods[J].Appl Opt,1996,35(30):6041-6053.
14 Tu Xinghua,Liu Wenqing,Wang Tiedong,et al..Noise analysis of second-harmonic detection with tunable diode laser absorption spectroscopy[J].Chinese J Quantum Electronics,2006,23(4):522 -526.涂兴华,刘文清,王铁栋,等.基于可调谐二极管激光吸收光谱学对二次谐波检测噪声分析研究[J].量子电子学报,2006,23(4):522-526.