Research on Fourier Transform Infrared Spectroscopy Processing Method Based on Butterworth Filter

Aiming at the problem of the performance degradation of Fourier transform infrared spectrometer due to the large signal noise interference, a Fourier transform infrared spectroscopy processing method based on Butterworth bandpass filter is proposed. First, the transfer function of the band-pass filter circuit is theoretically deduced, and then combined with the spectrometer parameters and the circuit software Multisim simulation to determine the specific values ​​of the circuit components, and further optimized through experiments until the design requirements are met, and finally the designed band-pass filter is used In the spectrometer, the signal-to-noise ratio of the instrument measured before and after adding the filter plate was compared and analyzed. The experimental results show that the infrared spectrum processing method based on Butterworth filter obtains the instrument signal-to-noise ratio in the 2100～2200 cm -1 and 2500～2600 cm -1 wavebands, respectively, as the instrument signal obtained by the traditional processing method without filter. The noise ratio is 1.83 times and 1.96 times. It shows that the new processing method effectively improves the signal-to-noise ratio of the instrument and improves the performance index of the instrument.