Single channel source separation of LFM and SFM mixed signal using fractional Fourier transform and zero phase filtering

To separate the mixture of two radar fuze signals - the linear frequency modulation (LFM) and sinusoidal frequency modulation (SFM) signals overlapped both in time and frequency domain in single channel, the method of zero phase filtering in fractional Fourier domain is proposed. The fractional Fourier transform (FRFT) of mixed signal is derived and it can be found that separation in the improved time-frequency distribution would be more effective, and then zero phase filtering is introduced to separate mixture which keeps the initial phase information. At last, by calculating the waveform similarity coefficient, the initial phase difference value and average amplitude difference value in the simulation, it is found that the proposed method is effective.