Application of \alpha-\beta-\gamma filtering to real-time atmosphere methane concentration measurement

A real time \alpha-\beta-\gamma filtering technique is applied to the monitoring of atmosphere CH_4 based on a tunable diode laser spectrum system operating at 1.654 \mum. This technique is developed for improving the sensitivity and precision of CH_4 concentration measurement with slow concentration change. The effectiveness of this technique is evaluated by performing CH_4 concentration measurement and using it to monitor the varying methane level in the atmosphere. It was proved that signal noise ratio enhancement factor is 4.25. The comparison between this filter and moving average is also included in this article. It indicates the advantage of the \alpha-\beta-\gamma real time filter.