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US 4,987,598 AGranted
Active acoustic attenuation system with overall modeling
AssigneeNelson Industries, Inc.
InventorLarry J. Eriksson
Life of this patent
Estimating the term…
Abstract
An active acoustic attenuation system (200) has a first adaptive filter model M modeling the acoustic path P from an input transducer (10) to an output transducer (14), and a second adaptive filter model Q modeling the overall system from the input transducer (10) to an error transducer (16). A third adaptive filter model T models the transfer function S of the output transducer (14) and the error path E between the output transducer (14) and the error transducer (16), without an auxiliary random noise source.
Claims23
An active acoustic attenuation method for attenuating an undesirable acoustic wave, comprising:
- sensing an input acoustic wave with an input transducer;
- introducing a canceling acoustic wave from an output transducer to attenuate said input acoustic wave and yield an attenuated output acoustic wave;
- sensing said output acoustic wave with an error transducer and providing an error signal;
- adaptively modeling the acoustic path from said input transducer to said output transducer with a first adaptive filter model having a model input from said input transducer, an error input from said error transducer, and a model output outputting a correction signal to said output transducer to introduce said canceling acoustic wave;
- adaptively modeling the acoustic path from said input transducer to said error transducer with a second adaptive filter model having a model input from said input transducer, an error input, and a model output combined with the output of said error transducer to provide an error signal to said error input of said second model.
2 more elements
A method for actively attenuating an undesirable acoustic wave, comprising:
- sensing an input acoustic wave with an input transducer;
- introducing a canceling acoustic wave from an output transducer to attenuate said input acoustic wave and yield an attenuated output acoustic wave;
- sensing said output acoustic wave with an error transducer and providing a first error signal;
- providing a first adaptive filter model having a model input from said input transducer, an error input provided by said first error signal, and a model output providing a correction signal to said output transducer to introduce said canceling acoustic wave;
- providing a second adaptive filter model having a model input from said input transducer, an error input, and a model output;
- providing a third adaptive filter model having a model input from the output of said first model, an error input, and a model output;
- combining the model outputs of said second and third models to yield a second error signal;
- combining said first and second error signals to yield a third error signal;
- providing said third error signal as the error input to each of said second and third models.
6 more elements
An active acoustic attenuation system for attenuating an undesirable acoustic wave, comprising:
- an input transducer for sensing an input acoustic wave;
- an output transducer introducing a canceling acoustic wave to attenuate said input acoustic wave and yield an attenuated output acoustic wave;
- an error transducer sensing said output acoustic wave and providing an error signal;
- a first adaptive filter model adaptively modeling the acoustic path from said input transducer to said output transducer, said first model having a model input from said input transducer, an error input from said error transducer, and a model output outputting a correction signal to said output transducer to introduce said canceling acoustic wave;
- a second adaptive filter model adaptively modeling the acoustic path from said input transducer to said error transducer, said second model having a model input from said input transducer, an error input, and a model output combined with the output of said error transducer to provide an error signal to said error input of said second model.
2 more elements
An active acoustic attenuation system for attenuating an undesirable acoustic wave, comprising:
- an input transducer for sensing an input acoustic wave;
- an output transducer introducing a canceling acoustic wave to attenuate said input acoustic wave and yield an attenuated output acoustic wave;
- an error transducer sensing said output acoustic wave and providing a first error signal;
- a first adaptive filter model having a model input from said input transducer, an error input provided by said first error signal, and a model output providing a correction signal to said output transducer to introduce said canceling acoustic wave;
- a second adaptive filter model having a model input from said input transducer, an error input, and a model output;
- a third adaptive filter model having a model input from the output of said first model, an error input, and a model output,
- wherein the model outputs of said second and third models are combined to yield a second error signal, and said first and second error signals are combined to yield a third error signal, and the error input of each of said second and third models is provided by said third error signal.
4 more elements
An active acoustic attenuation system for attenuating an undesirable acoustic wave, comprising:
- an input transducer for sensing an input acoustic wave;
- an output transducer having a transfer function S and spaced from said input transducer along an acoustic path P and introducing a canceling acoustic wave to attenuate said input acoustic wave and yield an attenuated output acoustic wave;
- an error transducer spaced from said output transducer along an error path E and sensing said output acoustic wave and providing an error signal;
- a first adaptive filter model M adaptively modeling said acoustic path P, model M having a model input from said input transducer, an error input from said error transducer, and a model output outputting a correction signal to said output transducer to introduce said canceling acoustic wave;
- a second adaptive filter model Q adaptively modeling P and E, model Q having a model input from said input transducer, an error input, and a model output;
- a third adaptive filter model T adaptively modeling S and E, model T having a model input from the output of model M, an error input, and a model output;
- a first summer summing the model outputs of models Q and T and yielding an output sum providing a second error signal;
- a second summer summing said first error signal and said second error signal to yield a second output sum providing a third error signal,
- wherein the error input of each of models Q and T is provided by said second output sum providing said third error signal.
6 more elements
Dependencies are inferred from the claim text.