空间外差光谱仪(SHS)所获取的干涉图像需经过傅里叶变换才能得到光谱信息。频域光谱的信噪比和光谱信号的质量很大程度上取决于干涉条纹调制度。针对干涉条纹调制度的影响因素进行了定量理论分析，包含分束器分束特性、光学系统像差（干涉组件面形误差、准直镜头输出面形误差及成像镜头调制传递函数曲线）、扩展光源及像元大小等。实验证明，空间外差光谱仪样机复原光谱实测结果与理论计算一致性较好，对干涉条纹调制度的定量分析为干涉型光谱仪各功能组件的设计提供了理论依据。

The spectral information of interferogram is obtained by Fourier transforms with spatial heterodyne spectrometer (SHS). So the spectrum signal to noise ratio and spectrum quality are directly influenced by interferogram modulation efficiency. In view of the influence factors of interference fringe modulation is carried on the theory of quantitative analysis, including splitting characteristics of beam splitter, aberrations of optical system (surface wavefront error of interferometer elements, output wavefront error of collimating lens and modulation transfer function curve of imaging lens), the extended source and pixel size of detector. Experimental result show that the measured result of recovering spectra by the SHS instrument is in agreement with the theoretical calculation. Quantitative analysis of the interference fringe modulation for interferometric spectrometer provides theory basis for the design of each function module.