傅里叶变换红外光谱仪干涉信号采集技术研究

Research on Interference Signal Acquisition of FTIR Spectrometer

针对傅里叶变换红外光谱仪中红外干涉信号在零光程差处出现峰值,零光程差外信号减弱与噪声相似,整体动态范围大这一特点,设计了基于分段增益控制的采集系统。通过程控增益放大模块以及基于FPGA的多路采集模块实现红外干涉信号的高动态范围采集。模拟干涉信号的测试表明该设计方案可以改善ZPD外弱信号采集,提高系统动态范围,还原真实光谱。

The character of infrared interference signal is that it appears its centerburst at the zero-path difference（ZPD）. Besides ZPD the strength of signal is weak and mixed with noise. A new acquisition method is proposed based on signal segmentation to improve dynamic range by PGA, dual ADC channels and FPGA module. Experiments show that the method can improve the acquisition quality of weak signal and has a high dynamic range and can restore the real spectrogram.