Fractional Delays using Lagrange Interpolators
| Autor: | Tassart, Stéphan, Depalle, Philippe |
|---|---|
| Přispěvatelé: | Analyse et synthèse sonores [Paris], Sciences et Technologies de la Musique et du Son (STMS), Institut de Recherche et Coordination Acoustique/Musique (IRCAM)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche et Coordination Acoustique/Musique (IRCAM)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), ircam, ircam |
| Jazyk: | francouzština |
| Rok vydání: | 1996 |
| Předmět: |
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph]
[SPI.ACOU] Engineering Sciences [physics]/Acoustics [physics.class-ph] fractional delays [SCCO.NEUR]Cognitive science/Neuroscience [SCCO.NEUR] Cognitive science/Neuroscience physical modeling signal processing [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing [SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing lagrange interpolation |
| Zdroj: | NAM 96 (Nordic Acoustical Meeting) NAM 96 (Nordic Acoustical Meeting), Jun 1996, Helsinki, Finlande. pp.315-321 |
| Popis: | cote interne IRCAM: Tassart96a; /; National audience; Many studies have been undertaken on the modeling of physical systems by means of waveguidefilters. These methods consist mainly in simulating the propagation of acoustic waves with digitaldelay lines. These models are constrained to have a spatial step determined by the sampling ratewhich is a serious drawback when a high spatial resolution in the geometry of the model is neededor when the length of the waveguide needs to vary. One can use digital filters for approximatingthe exact fractional delay, but length variations usually induce audible distortions because of localinstabilities or modification of the filter's structure. Lagrange Interpolation theory leads to FIR filters which approximate fractional delays accordingto a maximally flat error criterion. Major drawbacks of current implementations of LagrangeInterpolator Filters (LIF) are a high computation cost and a lack of control over the delay whichcan only vary in a narrow range of values. We propose a new implementation of LIF based on a formal power series expansion of the exactz-transform. We have developed different fast and modular algorithms for LIF which make theLIF usable for real-time delay-varying applications. Modularity in the structure is a key pointhere as it enables one to switch between filters of different order while preserving the continuityof the z-transform. Thus the delay may vary over an unlimited range of values. Furthermore, anyarbitrary integer part of the fractional delay can be simulated by a classical delay line so that theactual order of the LIF may be maintained within reasonable limits. This paper will focus on thetime-varying properties of our implementation and its numerical stability over a wide range ofdelays. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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