Multi-channel active attenuation system with error signal inputs

• US 5,216,722 A
• Filed: 11/15/1991
• Issued: 06/01/1993
• Est. Priority Date: 11/15/1991
• Status: Expired due to Term

• Current Assignee: Nelson Industries Incorporated (Cummins Incorporated)
• Original Assignee: Nelson Industries Incorporated (Cummins Incorporated)
• Inventors: Popovich, Steven R.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Lefkowitz, Edward
• Application Number:
  US07/794,115
• Time in Patent Office: 564 Days
• Field of Search: 381/71, 381/94
• US Class Current: 381/71.11
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17881 the reference signal being an acoustic signal, e.g. recorded with a microphone
• CPC Class Codes: G10K 11/17883 the reference signal being derived from a machine operating condition, e.g. engine RPM or vehicle speed
• CPC Class Codes: G10K 2210/103 Three dimensional
• CPC Class Codes: G10K 2210/3011 Single acoustic input
• CPC Class Codes: G10K 2210/3019 Cross-terms between multiple in's and out's
• CPC Class Codes: G10K 2210/3046 Multiple acoustic inputs, multiple acoustic outputs
• CPC Class Codes: G10K 2210/3049 Random noise used, e.g. in model identification
• CPC Class Codes: G10K 2210/3214 Architectures, e.g. special constructional features or arrangements of features

Abstract

A multi-channel active acoustic attenuation system for attenuating a correlated input acoustic wave has one or more output transducers introducing one or more respective canceling acoustic waves to attenuate the input acoustic wave and yield an attenuated output acoustic wave, one or more error transducers sensing the output acoustic wave and providing one or more error signals, and a plurality of adaptive filter channel models. Each channel model has a model input from a respective error transducer. One or more of the channel models also has a model input from at least one of the remaining channel models. Each channel model has an error input from one or more of the error transducers. Each channel model has a model output outputting a correction signal to a respective output transducer to introduce the respective canceling acoustic wave. The correction signal from one or more of the model outputs is also input to the model input of one or more of the remaining channel models.

Claims

1. A multi-channel active acoustic attenuation system for attenuating a correlated input acoustic wave, comprising:

at least one output transducer introducing at least one respective canceling acoustic wave to attenuate said input acoustic wave and yield an attenuated output acoustic wave;

a plurality of error transducers sensing said output acoustic wave and providing respective error signals;

a plurality of adaptive filter channel models, each channel model having a model input from a respective said error transducer, an error input from a plurality of said error transducers, and a model output outputting a correction signal to a respective said output transducer to introduce the respective said canceling acoustic wave;

first and second error transducers, and first and second channel models, said first channel model having a model input from said first error transducer, said first channel model having an error input from each of said first and second error transducers, said first channel model having a model output, said second channel model having a model input from said second error transducer, said second channel model having an error input from each of said first and second error transducers, said second channel model having a model output summed with said model output of said first channel model to provide a resultant sum supplied as a correction signal to a respective said output transducer.

2. A multi-channel active acoustic attenuation system for attenuating a correlated input acoustic wave, comprising:

a plurality of output transducers introducing a plurality of canceling acoustic waves to attenuate said input acoustic wave and yield an attenuated output acoustic wave;

at least one error transducer sensing said output acoustic wave and providing at least one respective error signal;

a plurality of adaptive filter channel models, each channel model having a model output outputting a correction signal to a respective said output transducer to introduce the respective said canceling acoustic wave, an error input from a respective said error transducer, and a model input from a respective said error transducer and also from a model output of at least one of the remaining channel models;

first and second output transducers, and first and second channel models, said first channel model having a model output outputting a correction signal to said first output transducers, said first channel model having an error input from the respective said error transducer, said first channel model having a model input from the respective said error transducer and also from the model output of said first channel model and also from the model output of said second channel model, said second channel model having a model output outputting a correction signal to said second output transducer, said second channel model having an error input from the respective said error transducer, said second channel model having a model input from the respective said error transducer and also from the model output of said second channel model and also from the model output of said first channel model.

3. A multi-channel active acoustic attenuation system for attenuating a correlated input acoustic wave, comprising:

first and second output transducers introducing first and second canceling acoustic waves to attenuate said input acoustic wave and yield an attenuated output acoustic wave;

first and second error transducers sensing said output acoustic wave and providing first and second error signals;

a first adaptive filter channel model having a model input from said first error transducer, an error input from each of said first and second error transducers, and a model output outputting a correction signal to said first output transducer;

a second adaptive filter channel model having a model input from said second error transducer, an error input from each of said first and second error transducers, and a model output outputting a correction signal to said first output transducer;

a third adaptive filter channel model having a model input from said second error transducer, an error input from each of said first and second error transducers, and a model output outputting a correction signal to said second output transducer;

a fourth adaptive filter channel model having a model input from said first error transducer, an error input from each of said first and second error transducers, and a model output outputting a correction signal to said second output transducer.

4. The system according to claim 3 wherein:

said correction signals from said first and second channel models are supplied to each of said model inputs of said first, second, third and fourth channel models;

said correction signals from said third and fourth channel models are supplied to each of said model inputs of said first, second, third and fourth channel models.

5. The system according to claim 3 comprising:

a first summer summing said correction signals from said first and second channel models and providing an output resultant sum;

a second summer summing said correction signals from said third and fourth channel models and providing an output resultant sum;

a third summer summing the outputs of said first and second summers and providing an output resultant sum;

a fourth summer summing the outputs of said first and second summers and providing an output resultant sum;

a fifth summer summing the output of said third summer and the output of said first error transducer and providing an output resultant sum to said model input of said first channel model and also to said model input of said fourth channel model;

a sixth summer summing the output of said fourth summer and the output of said second error transducer and providing an output resultant sum to said model input of said third channel model and also to said model input of said second channel model.

6. The system according to claim 5 wherein:

said first channel model comprises a first set of error path models of error paths between said first output transducer and each of said first and second error transducers, said first set comprising a first error path model having an input from said first error transducer, said first error path model having an output multiplied at a first multiplier with the output of said first error transducer, said first set comprising a second error path model having an input from said first error transducer, said second error path model having an output multiplied at a second multiplier with the output of said second error transducer, the outputs of said first and second multipliers being summed at a seventh summer providing an output resultant sum to said error input of said first channel model;

said second channel model comprises a second set of error path models of error paths between said first output transducer and each of said first and second error transducers, said second set comprising a third error path model having an input from said second error transducer, said third error path model having an output multiplied at a third multiplier with the output of said first error transducer, said second set comprising a fourth error path model having an input from said second error transducer, said fourth error path model having an output multiplied at a fourth multiplier with the output of said second error transducer, the outputs of said third and fourth multipliers being summed at an eighth summer providing an output resultant sum to said error input of said second channel model;

said third channel model comprises a third set of error path models of error paths between said second output transducer and each of said first and second error transducers, said third set comprising a fifth error path model having an input from said second error transducer, said fifth error path model having an output multiplied at a fifth multiplier with the output of said second error transducer, said third set comprising a sixth error path model having an input from said second error transducer, said sixth error path model having an output multiplied at a sixth multiplier with the output of said first error transducer, the outputs of said fifth and sixth multipliers being summed at a ninth summer providing an output resultant sum to said error input of said third channel model;

said fourth channel model comprises a fourth set of error path models of error paths between said second output transducer and each of said first and second error transducers, said fourth set comprising a seventh error path model having an input from said first error transducer, said seventh error path model having an output multiplied at a seventh multiplier with the output of said second error transducer, said fourth set comprising an eighth error path model having an input from said first error transducer, said eighth error path model having an output multiplied at an eighth multiplier with the output of said first error transducer, the outputs of said seventh and eighth multipliers being summed at a tenth summer providing an output resultant sum to said error input of said fourth channel model;

and comprising;

a ninth error path model having an input from the output of said first summer, said ninth error path model having an output supplied to said third summer;

a tenth error path model having an input from the output of said second summer, said tenth error path model having an output supplied to said third summer;

an eleventh error path model having an input from the output of said second summer, said eleventh error path model having an output supplied to said fourth summer;

a twelfth error path model having an input from the output of said first summer, said twelfth error path model having an output supplied to said fourth summer.

7. A multi-channel active acoustic attenuation method for attenuating a correlated input acoustic wave, comprising:

introducing at least one canceling acoustic wave from at least one respective output transducer to attenuate said input acoustic wave and yield an attenuated output acoustic wave;

sensing said output acoustic wave with a plurality of error transducers and providing respective error signals;

providing a plurality of adaptive filter channel models, providing each channel model with a model input from a respective said error transducer, providing each channel model with an error input from a plurality of error transducers, and providing each channel model with a model output outputting a correction signal to a respective said output transducer to introduce the respective said canceling acoustic wave;

providing first and second error transducers, said first and second channel models, providing said first channel model with a model input from said first error transducer, providing said first channel model with an error input from each of said first and second error transducers, providing said first channel model with a model output, providing said second channel model with a model input from said second error transducer, providing said second channel model with an error input from each of said first and second error transducers, providing said second channel model with a model output, summing said model output of said second channel model with said model output of said first channel model and supplying the resultant sum as a correction signal to a respective said output transducer.

8. A multi-channel active acoustic wave, comprising:

introducing a plurality of canceling acoustic waves for attenuating a correlated input acoustic wave, comprising;

introducing a plurality of canceling acoustic waves from a plurality of output transducers to attenuate said input acoustic wave and yield an attenuated output acoustic wave;

sensing said output acoustic wave with at least one error transducer and providing at least one respective error signal;

providing a plurality of adaptive filter channel models, providing each channel model with a model output outputting a correction signal to a respective said output transducer to introduce the respective said canceling acoustic wave, providing each channel model with an error input from a respective said error transducer, and providing each channel model with a model input from a respective said error transducer and also from a model output of at least one of the remaining channel models;

providing first and second output transducers, and first and second channel models, providing said first channel model with a model output outputting a correction signal to said first output transducer, providing said first channel model with an error input from the respective said error transducer, providing said first channel model with a model input from the respective said error transducer and also from the model output of said first channel model and also from the model output of said second channel model, providing said second channel model with a model output outputting a correction signal to said second output transducer, providing said second channel model with an error input from the respective said error transducer, providing said second channel model with a model input from the respective said error transducer and also from the model output of the second channel model and also from the model output of said first channel model.

9. A multi-channel active acoustic attenuating method for attenuating a correlated input acoustic wave, comprising:

introducing first and second canceling acoustic waves from first and second output transducers to attenuate said input acoustic wave and yield an attenuated output acoustic wave;

sensing said output acoustic wave with first and second error transducers and providing first and second error signals;

providing a first adaptive filter channel model, providing said first channel model with a model input from said first error transducer, providing said first channel model with an error input from each of said first and second error transducers, providing said first channel model with a model output and outputting a correction signal to said first output transducer;

providing a second adaptive filter channel model, providing said second channel model with a model input from said second error transducer, providing said second channel model with an error input from each of said first and second error transducers, providing said second channel model with a model output and outputting a correction signal to said first output transducer;

providing a third adaptive filter channel model, providing said third channel model with a model input from said second error transducer, providing said third channel model with an error input from each of said first and second error transducers, providing said third channel model with a model output and outputting a correction signal to said second output transducer;

providing a fourth adaptive filter channel model, providing said fourth channel model with a model input from said first error transducer, providing said fourth channel model with an error input from each of said first and second error transducers, providing said fourth channel model with a model output and outputting a correction signal to said second output transducer.

10. The method according to claim 9 comprising:

supplying said correction signals from said first and second channel models to each of said model inputs of said first, second, third and fourth channel models;

supplying said correction signals from said third and fourth channel models to each of said model inputs of said first, second, third and fourth channel models.

11. The method according to claim 9 comprising:

summing said correction signals from said first and second channel models at a first summer and providing an output resultant sum;

summing said correction signals from said third and fourth channel models at a second summer and providing an output resultant sum;

summing the outputs of said first and second summers at a third summer and providing an output resultant sum;

summing the outputs of said first and second summers at a fourth summer and providing an output resultant sum;

summing the output of said third summer and the output of said first error transducer at a fifth summer and providing an output resultant sum to said model input of said first channel model and also to said model input of said fourth channel model;

summing the output of said fourth summer and the output of said second error transducer at a sixth summer and providing an output resultant sum to said model input of said third channel model and also to said model input of said second channel model.

12. The method according to claim 11 comprising:

providing said first channel model with a first set of error path models of error paths between said first output transducer and each of said first and second error transducers, providing said first set with a first error path model, providing said first error path model with an input from said first error transducer, providing said first error path model with an output, multiplying the output of said first error path model and the output of said first error transducer at a first multiplier, providing said first set with a second error path model, providing said second error path model with an input from said first error transducer, providing said second error path model with an output, multiplying the output of said second error path model and the output of said second error transducer at a second multiplier, summing the outputs of said first and second multipliers at a seventh summer and providing an output resultant sum to said error input of said first channel model;

providing said second channel model with a second set of error path models of error paths between said first output transducer and each of said first and second error transducers, providing said second set with a third error path model, providing said third error path model with an input from said second error transducer, providing said third error path model with an output, multiplying the output of said third error path model and the output of said first error transducer at a third multiplier, providing said second set with a fourth error path model, providing said fourth error path model with an input from said second error transducer, providing said fourth error path model with an output, multiplying the output of said fourth error path model with the output of said second error transducer at a fourth multiplier, summing the outputs of said third and fourth multipliers at an eighth summer and providing an output resultant sum to said error input of said second channel model;

providing said third channel model with a third set of error path models of error paths between said second output transducer and each of said first and second error transducers, providing said third set with a fifth error path model, providing said fifth error path model with an input from said second error transducer, providing said fifth error path model with an output, multiplying the output of said fifth error path model and the output of said second error transducer at a fifth multiplier, providing said third set with a sixth error path model, providing said sixth error path model with an input from said second error transducer, providing said sixth error path model with an output, multiplying the output of said sixth error path model and the output of said first error transducer at a sixth multiplier, summing the outputs of said fifth and sixth multipliers at a ninth summer and providing an output resultant sum to said error input of said third channel model;

providing said fourth channel fourth set of error path models of error paths between said second output transducer and each of said first and second error transducers, providing said fourth set with a seventh error path model having an input from said first error transducer, providing said seventh error path model with an output, multiplying the output of said seventh error path model and the output of said second error transducer at a seventh multiplier, providing said fourth set with an eighth error path model, providing said eighth error path model with an input from said first error transducer, providing said eighth error path model with an output, multiplying the output of said eighth error path model and the output of said first error transducer at an eighth multiplier, summing the outputs of said seventh and eighth multipliers and providing an output resultant sum to said error input of said fourth channel model;

providing a ninth error path model having an input and an output, supplying the output of said first summer to the input of said ninth error path model, supplying the output of said ninth error path model to said third summer;

providing a tenth error path model having an input and an output, supplying the output of said second summer to the input of said tenth error path model, supplying the output of said tenth error path model to said third summer;

providing an eleventh error path model having an input and an output, supplying the output of said second summer to the input of said eleventh error path model, supplying the output of said eleventh error path model to said fourth summer;

providing a twelfth error path model having an input and an output, supplying the output first summer to the input of said twelfth error path model, supplying the output of said twelfth error path model to said fourth summer.