中文摘要：

由于线宽窄,可调谐半导体激光吸收光谱技术（TDLAS）一般情况下只能对一种气体进行检测.为了实现多气体同时或近同时在线检测,本文以1 578 nm H2S和1 747 nm-HCl混合气体同时在线监测为例,研究了3种检测方法：（1）同频10 kHz正弦波和两路同频30 Hz不同步的分时锯齿信号法;（2）同频10 kHz正弦和30 Hz锯齿信号的光开关检测法;（3）多频（10 kHz和20 kHz正弦信号）正弦调制法.实验结果表明：分时锯齿信号法除幅值略有微小变化外,在使用前后对测试结果影响很小;光开关法在切换过程瞬间会略有不稳定,但不影响后期的浓度反演;多频正弦法的信噪比和抗干扰能力均有所提高,进行HCl探测和H2S探测时,信噪比在激光器关闭和打开情况下分别提高了0.95倍和3.17倍.以上3种方法操作简单,可以方便地实现多气体组分的同时在线监测,提高了TDLAS仪器的竞争力.

英文摘要：

Generally, Tunable Diode Laser Absorption Spe kind of gas because of its narrow line-width. To detect the ctroscopy （TDLAS） can detect only one multi-component gas in real time simulta- neously or near simultaneously, three kinds of detection methods were reported by taking 1 578 nm- H2S, 1 747 nm-HC1 and N2 mixture for examples. The three methods are called timeshare-sawtooth method （10 kHz sin wave, 30 Hz asynchrony sawtooth wave）, optical-switch method （same frequency 10 kHz sin wave, 30 Hz sawtooth wave） and multi-frequency modulation method （10 kHz and 20 kHz sin wave）. The experimental results for the three methods show as follows： the method one gives fe- wer effects on measuring results apart from amplitude changes. The method 2 shows slightly unstable moments in the the experiment. ence ability are switching process, but it has no effect on concentration Moreover, in the method 3, the Si improved, and the SNR has increase g d nal-to-noise Ratio inversion in the （SNR） and the later stage of anti-interfer- about 0.95 and 3.17 times for monitoring HC1 and H2S when lasers are on or off. The three methods mentioned above have advantages on less in vestment, simple adjusting, and easy operation, also they can monitor many kinds of gases with the changing modulation parameters or switch channels, simultaneously