Experimental study on harmonic detection of methane by use of a digital lock-in amplifier
Dong, L.; Ma, W.-G.; Yin, W.-B.; Li, C.-y.; Jia, S.-t.
Guang Pu Xue Yu Guang Pu Fen Xi 25(3): 473-476
The harmonic detection of methane at 6105.3694 cm(-1) was measured by use of a digital lock-in amplifier (SR830) remotely controlled by a computer. The programme was written by Visual Basic 6.0 because it has strong function and a friendly appearance. The experimental results are in agreement with theoretical analysis, which fully confirms that a better signal-to-noise ratio (SNR) can be achieved in the high-harmonics detection of trace gases by the digital lock-in amplifier. The method can be applicable to the highly sensitive detection of pollution gases.