title: Ramanujan sums for signal processing of low-frequency noise.
abstract: An aperiodic (low-frequency) spectrum may originate from the error term in the mean value of an arithmetical function such as Möbius function or Mangoldt function, which are coding sequences for prime numbers. In the discrete Fourier transform the analyzing wave is periodic and not well suited to represent the low-frequency regime. In place we introduce a different signal processing tool based on the Ramanujan sums c(q)(n), well adapted to the analysis of arithmetical sequences with many resonances p/q. The sums are quasiperiodic versus the time n and aperiodic versus the order q of the resonance. Different results arise from the use of this Ramanujan-Fourier transform in the context of arithmetical and experimental signals.
authors.affiliation: Laboratoire de Physique et Métrologie des Oscillateurs du CNRS, 32 Avenue de l'Observatoire, 25044 Besançon Cedex, France. planat@lpmo.edu
authors.forename: Michel
authors.initials: M
authors.lastname: Planat
authors.forename: Haret
authors.initials: H
authors.lastname: Rosu
authors.forename: Serge
authors.initials: S
authors.lastname: Perrine