为了解决现有TDLAS气体检测系统体积庞大、集成度低的缺点并实现系统的小型化, 研制了一套基于FPGA的TDLAS气体检测系统, 采用模块化设计方法,将电流驱动、温度控制、信号调理、锁相放大等功能有机地集成于一体, 实现了激光输出和微弱信号解调的全自动化。同时, 研制的TDLAS气体检测系统小型化程度高、成本低, 利于小型化和推广。实验结果表明, 该气体检测系统检测性能良好, 二次谐波信号与湿度的线性拟合度达99.94%。在湿度为30%的条件下, 测量结果的标准差为3.23×10-3, 系统具备良好的稳定性。在此条件下, 系统背景噪声为5 mV, 信噪比达到36 dB。

In order to overcome the shortcomings of large volume and low integration of the existing TDLAS (tunable diode laser absorption spectrometry) gas detection system and realize the miniaturization of the system, a FPGA-based TDLAS gas detection system is developed. The current driving, temperature control, signal conditioning and phase-locked amplification are integrated organically by using modular design method. Hence laser output and weak signal demodulation can be realized automatically. Meanwhile the proposed TDLAS gas detection system has high-level integration and low cost, helpful for miniaturization and promotion. The experimental results show that the gas detection system has good detection performance, and the linearly fit of the second harmonic signal to humidity is 99.94%. Under the condition of humidity of 30%, the standard deviation of the measurement results is 3.23×10-3, verifying good stability of the system. In addition, the system background noise is 5 mV, and the signal-to-noise ratio reaches 36 dB.