Représentations temps-fréquence adaptées aux ondes guidées
Time-Frequency Representations matched to guided waves
OPEN ACCESS
Recent progress on time-frequency representation (TFR) are based on adapted methods. We develop an original methodology based on physics of propagation in Underwater Acoustics. We present first the methodology for guided waves. We build then matched TFR to the Perfect Waveguide and to the Pekeris Waveguide which both describe wave propagation on Ultra Low Frequency (1-100 Hz) on UA shallow water environment. We test those methods on real pressure signals. We evaluate finally the built TFR and we study their limits.
Résumé
Les progrès récents en représentation temps-fréquence (RTF) reposent sur la mise au point de méthodes adaptées aux signaux traités. Nous développons ici une méthodologie originale dans laquelle la RTF est supervisée par les connaissances a priori issues de la physique de la propagation des ondes en Acoustique Sous-Marine (ASM). Nous présentons d'abord la méthodologie générale des RTF adaptées applicables aux signaux propagés dans un guide d'ondes. Nous construisons ensuite des RTF adaptées au guide parfait (guide sans perte) et au guide de Pekeris [1] qui décrivent tous deux la propagation des ondes d'Ultra Basse Fréquence (1-100 Hz) en ASM dans un environnement petit fond. Nous testons ces méthodes sur des signaux réels. Nous évaluons enfin les RTF construites et exposons leurs limites.
Time-Frequency Representations, guided waves, modal filtering
Mots clés
Représentations temps-fréquence, ondes guidées, filtrage modal
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