Séminaire équipe IPI – invité Imants SVALBE (Monash University)
12 janvier 2018 @ 16 h 30 min - 17 h 30 min
L’équipe IPI accueille Imants Svalbe, professeur au sein de la « School of Physics and Astronomy » (Monash University, Australie).
Ce dernier animera un séminaire vendredi 12 janvier de 16h30 à 17h30 dans la salle D005 du bâtiment IRESTE à Polytech.
Résumé : A function that has equal amplitude (or power) at all Nyquist frequencies in its periodic Fourier transform is called ‘spectrally flat’. White noise is one practical example that approximates this condition, as too do random sequences. The Dirac delta is the obvious exact example. The auto-correlation of any spectrally flat function is a delta function. A perfectly sharp correlation response from a long sequence or a signal with a large volume permits very precise synchronisation or alignment in time or space. Long, spectrally flat 1D sequences can be folded into nD arrays that are spectrally flat. Other forms of exact spectrally flat functions are presented. Extended multiple-matched filters provide further examples. The discrete projective Finite Radon transform is especially useful in fabricating arrays that are spectrally flat. Such arrays are used in the design of send/receive antennae in digital communications, for image encryption and in digital watermarking.
