The LFM signal and noise could be separated more effectively by FRFT than by traditional FFT.The energy gathering of FRFT spectrum is effected by duty ratio and FM bandwidth.With small duty ratio and wide FM bandwidth

the spectrum peak of FRFT would not be very sharp.The article presents a new slipping window way used in fractional Fourier filtering of LFM signal.The effect of time and frequency intercept in FRFT is also analyzed.A differentiation principle used in LFM signal detection under the condition of low SNR is provided based on the analysis before.Also

the filtering process in fractional Fourier domain is discussed in detail.It is indicated by the emulation result that blind signal could be processed by the filtering way in pipelining mode with little noise energy.The SNR could increase more than 10dB.It also indicates that the effect is improved in radar deception jamming domain.