激光技术Issue(4)：498-502,5.DOI:10.7510/jgjs.issn.1001-3806.2013.04.018
调制相位差对TDLAS信噪比的影响
Effect of modulated phase difference on TDLAS signal-to-noise ratio
董跃辉 1吴尚谦 1翟维 1皇甫张棣 1刘爱英1
作者信息
摘要
Abstract
When using tunable diode laser absorption spectroscopy ( TDLAS) for gas detection, modulation phase difference would make the result different .In order to improve harmonic wave detection sensitivity , frequency modulation and amplitude modulation were simultaneously chosen to analyze and extract the second harmonic wave signal .The functional relationship expression between the phase difference and the photo -electron current of the second harmonic wave and the residual amplitude modulation noise was also derived .From the simulation experiments, the variation trend of the second harmonic wave signal and the residual amplitude modulation noise with the phase difference were obtained .And then, the effect of phase difference on signal-to-noise ratio(SNR) was analyzed.The results show that the phase difference between amplitude modulation and frequency modulation has a significant impact on SNR .The largest drop is 59.18%when compared with the typical value of phase difference of π/2.Modulation phase difference is another important affecting factor of SNR besides residual amplitude modulation .关键词
光谱学/相位差/频率调制/可调谐二极管激光吸收光谱/信噪比Key words
spectroscopy/phase difference/frequency modulation/tunable diode laser absorption spectroscopy/signal-to-noise ratio分类
数理科学引用本文复制引用
董跃辉,吴尚谦,翟维,皇甫张棣,刘爱英..调制相位差对TDLAS信噪比的影响[J].激光技术,2013,(4):498-502,5.
