Development of on-line auto gas detection system based on AOTf

摘要

In this paper, the basic dispersion principle of AOTF (Acousto - Optic Tunable Filter) and the configuration of on-line auto gas detection system based on it are generally described. The off-axial reflection paraboloid mirror employed as the collimation system of light source avoids the light energy loss and spherical aberration. The filament length of infrared light source is limited to 5.2mm for separating incident light beam from diffracted light beam spatially. In this paper, DDS (Direct Digital Synthesizer) measure to be used to realize wavelength scan, an interface circuit between DDS and DSP (Digital Signal Processor) is introduced. Experiment results show that this system based on AOTF has 4000 -2000cm~(-1) wavelength range with 15cm~(-1) spectral resolution and 0.3ms wavelength transfer rate. This system has already been satisfactory for detecting auto gas on-line.