Research on Modulation Frequency and Scanning Frequency Parameters Selection of TDLAS System

Abstract

The modulation frequency and scanning frequency effect on the detection signal of tunable diode laser absorption spectroscopy (TDLAS) system is studied. The experiment system is designed to detect carbon dioxide (CO2). This paper analyzes the relationship between scanning frequency and modulation frequency and researches correlation theory. When modulation frequency and scanning frequency take different values, the change of the second harmonic (2f) signal waveform, maximum amplitude, signal-to-noise ratio (SNR), peak width and peak height ratio (PHR) are studied by experiment. It provides the theory and experiment basis for the selection of two parameters of TDLAS harmonic detection method.