In this paper

the affects of the match Fourier transform on moise are discussed

Theoretical analyses and simulations indicate that the match Fourier transform can enlarge the bandwidth of the coloured noise and compress the bandwidth of the matched signal

which improves the performance of detecting signal.Because the distribution of signal and noise is dissimilar in the different match Fourier field

so the filter can be made in the different match Fourier field to get better performance.The simulations show that under the condition of S/N=-20dB

if the chirp signal is filtered time after time in the different match Fourier field

the signal may be over 15dB more than noise.