The Algorithm of LFM Interference Suppression Based on FrFT
Cheng Naipin · Journal of Academy of Equipment · 2014
The threshold value setting is a challenge when interference suppression based on fractional Fourier transform(FrFT).In order to suppress the linear frequency modulated(LFM)interference of DS/FH,a novel algorithm to suppress the LFM interference is presented by analyzing the FrFT properties of DS/FH signal and LFM signal.The algorithm uses the properties that FrFT is the axis rotation in the time-frequency domain.First,calculates each order FrFT of the signal,and searches for the peak value;secondly,determines the optimal signal FrFT order by comparing each peak value;at last,rules out LFM interference signals and uses the frequency domain notch filter to suppress LFM interference.Theoretical analysis and simulation experiments show that this algorithm can effectively eliminate the LFM interference signal in the DS/FH system.It doesn’t need to set the threshold and it also has better robustness and applicability.