波长调制光谱是一种高灵敏光谱检测技术，针对典型应用条件的精确信号分析模型可以为光谱检测系统的设计和优化提供依据。在Fourier分析的基础上给出了可调谐半导体激光波长调制光谱技术的理论描述。分析了可调谐半导体激光正弦频率调制情况下WMS各次谐波信号特征，研究了激光幅度调制对谐波信号的影响，以及由系统光学表面标准具效应引入的背景噪声与量化描述。分析方法不受调制幅度的限制，适合于不同条件下波长调制光谱分析和背景信号的定量分析。

Wavelength modulation spectroscopy(WMS) is a high sensitive spectral detection technique, and a precise signal analysis model for the typical application is the basis for system design and optimization. A theoretical description based on Fourier analysis of tunable diode laser wavelength modulation spectroscopy technique is given. The characteristics of WMS harmonics of tunable diode laser spectroscopy under sinusoidal frequency modulated are analyzed, and the influences of laser amplitude modulation and etalon effect of system various optical surfaces on the harmonic signals are studied. The formalism is not confined by the modulation amplitude, and can quantitatively elucidate WMS analysis and background signals under arbitrary situations.