傅里叶变换红外光谱技术由于具有光通量大、光谱范围宽、分辨率高等诸多优势,在 大气环境监测领域得到广泛应用。以傅里叶变换红外光谱仪微弱红外干涉光信号特征和碲镉汞光电导型红外探测器为 基础,分析了基于迈克逊干涉方法的傅里叶变换光谱仪干涉光信号特征,设计了一种以窄带滤波法为核心的微弱信号检 测电路,建立了等效噪声模型分析电路的噪声性能。采用Tina软件对电路进行了模拟仿真,结果表明该电路在通频带内具 有恒定的增益以及群时延,可实现微弱干涉信号无失真放大。将设计的电路应用于傅里叶变换光谱仪中,在室温条件下 获得了大气400～7000 cm-1中红外波段光谱,几乎覆盖了常见的大气污染物在中红外波段的吸收峰,可以较好 地实现对不同污染气体的分辨与测量。

Due to large flux, wide spectral range, high resolution and many other advantages, Fourier transform infrared spectroscopy has been widely used in the field of atmospheric environment monitoring. Based on the weak infrared interference optical signal characteristic of Fourier transform infrared spectrometer and the tellurium cadmium mercury photoconductive type infrared detector, the characteristics of the interference optical signal of the Fourier transform spectrometer based on the Michelson interference method are analyzed. A kind of weak signal detection circuit taking narrowband filtering method as the core is designed, and the equivalent noise model is established to analyze the noise performance of the circuit. The circuit is simulated by Tina software. Results show that the circuit has constant gain and group delay in the pass band, and the weak interference signal can be amplified without distortion.The designed circuit is applied to the Fourier transform spectrometer, and the atmospheric mid-infrared band spectrum ranging from 400～7000 cm-1 is obtained at room temperature, almost covering the common absorption peak of atmospheric pollutants in the mid-infrared band, which can achieve the identification and measurement of different pollutants.