Effect Analysis of the Core Algorithm in Fast Fourier Transform Spectrometer (FFTS)

Fast Fourier transform spectrometer (FFTS) is a digital spectrometer technology that can perform multi-channel spectral analysis. The power spectrum can be obtained after analog-to-digital conversion and fast Fourier transform (FFT) by means of the board with integrated chips. The core radix 16 real-time complex FFT algorithm can be used for real-time data processing, which can parallelize and pluralize the front-end input signal. The parallelized processing can fully improve the computing efficiency, while the pluralized processing can save hardware resources. The sensitivity is the important parameter of hyperspectral microwave radiometer, characterizing the minimum brightness temperature that the system can resolve in the frequency domain. In this research, the impact of the core algorithm in FFTS on system sensitivity is further analyzed through the four sensitivity calculation methods we defined previously. By setting different simulation conditions, the results show that for the subband, the core algorithm in FFTS causes the deterioration of the sensitivity for each channel, and the average values of the sub-band sensitivity deterioration ratios fluctuate between 10% and 20%