CAJ | 학술논문

针对准连续激光调制吸收光谱谐波信号的解调，设计了一种专用的准连续软件锁相放大器，对采集的数据做有效性判断、无效数据滤除、数字相敏检测、数字滤波等处理，实现了准连续激光调制吸收光谱的谐波信号解调。构建气体检测实验系统，对准连续软件锁相放大器和商品化的高性能锁相放大器进行了对比实验，结果表明，使用准连续软件锁相放大器的A llan方差比后者小1个数量级、检测限低2倍。并能够解决小占空比时的信号失锁问题，具有小的信号波形失真。
침대준련속격광조제흡수광보해파신호적해조，설계료일충전용적준련속연건쇄상방대기，대채집적수거주유효성판단、무효수거려제、수자상민검측、수자려파등처리，실현료준련속격광조제흡수광보적해파신호해조。구건기체검측실험계통，대준련속연건쇄상방대기화상품화적고성능쇄상방대기진행료대비실험，결과표명，사용준련속연건쇄상방대기적A llan방차비후자소1개수량급、검측한저2배。병능구해결소점공비시적신호실쇄문제，구유소적신호파형실진。
A software phase-locked amplifier demodulation method is proposed in order to demodulate the second harmonic (2 f) signal of quasi-continuous laser wavelength modulation spectroscopy (WMS) properly ,based on the analysis of its signal charac-teristics .By judging the effectiveness of the measurement data ,filter ,phase-sensitive detection ,digital filtering and other pro-cessing ,the method can achieve the sensitive detection of quasi-continuous signal .The method was verified by using carbon diox-ide detection experiments .The WMS-2 f signal obtained by the software phase-locked amplifier and the high-performance phase-locked amplifier (SR844) were compared simultaneously .The results show that the Allan variance of WMS-2 f signal demodula-ted by the software phase-locked amplifier is one order of magnitude smaller than that demodulated by SR844 ,corresponding two order of magnitude lower of detection limit .And it is able to solve the unlocked problem caused by the small duty cycle of quasi-continuous modulation signal ,with a small signal waveform distortion .