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US 8,280,065 B2Granted
Method and system for active noise cancellation
AssigneeSemiconductor Components Industries, LLC
InventorsHamid Sheikhzadeh Nadjar, Todd Schneider, Robert L. Brennan
Life of this patent
Estimating the term…
Abstract
A method and system for active noise cancellation is provided. The system employs subband processing, and preferably implements over-sampled filterbank. The system is applicable to adaptive noise cancellation, adaptive echo cancellation for portable listening devices, such as headsets and other similar listening devices.
Claims25
A system for active noise cancellation, comprising:
- an analog active noise cancellation (ANC) system for performing an active noise cancellation to a primary signal in a time-domain, the primary signal being associated with an acoustic signal and comprising noise;
- a first analysis filter bank for transferring a reference signal in the time-domain into a plurality of subband reference signals in a frequency-domain, the reference signal being associated with the noise;
- a second analysis filter bank for transferring the primary signal in the time-domain into a plurality of subband primary signals in the frequency-domain;
- a subband processing module for processing the plurality of subband reference signals, the plurality of subband primary signals or a combination thereof, including detecting the analog ANC system at brink of instability, and adjusting one or more parameters of the analog ANC system based on the processing, the subband processing module comprising:
- a subband estimator for estimating a subband acoustic transfer function, the subband acoustic transfer function modelling conversion of an electrical signal into an acoustic domain signal, the subband estimator being applied to the plurality of subband reference signals;
- a subband adaptive filter for providing a plurality of subband output signals in response to the plurality of subband reference signals;
- an adjustor for adjusting the subband adaptive filter in response to the plurality of subband primary signals and the plurality of estimated subband reference signals;
- and
- a synthesis filter bank for transferring the plurality of subband output signals to a time-domain output signal.
6 more elements
A system for active noise cancellation, comprising:
- an analog active noise cancellation (ANC) system for performing an active noise cancellation to a primary signal in a time-domain, the primary signal being associated with an acoustic signal and comprisinq noise;
- an analysis filterbank for transferring the primary signal in the time-domain into a plurality of subband primary signals in a frequency-domain;
- a subband processing module for processing the plurality of subband primary signals, including detecting the analog ANC system at brink of instability, and adjusting one or more parameters of the analog ANC system based on the processing, the subband processing module comprising:
- a subband adaptive filter for providing a plurality of subband output signals in response to a plurality of subband reference signals;
- a feed-back loop for adapting the subband adaptive filter, including:
- a first subband estimator for estimating a subband acoustic transfer function, the subband acoustic transfer function modelling conversion of an electrical signal into an acoustic domain signal, the first subband estimator being applied to the plurality of subband output signals;
- a signal path for generating the plurality of subband reference signals in response to the plurality of subband primary signals and the plurality of estimated subband output signals;
- a second subband estimator for estimating the subband acoustic transfer function, the second subband estimator being applied to the plurality of subband reference signals;
- and
- an adjustor for adjusting the subband adaptive filter in response to the plurality of subband primary signals and the plurality of estimated subband reference signals;
- and
- a synthesis filterbank for transferring the plurality subband output signals into a time-domain output signal.
9 more elements
A system for active noise cancellation, comprising:
- a first analysis filterbank for transferring a primary signal in a time-domain into a plurality of subband primary signals in a frequency-domain;
- a second analysis filterbank for transferring a reference signal in the time-domain into a plurality of subband reference signals in the frequency-domain;
- a time-domain adaptive filter for providing a time-domain output signal in response to the reference signal in the time-domain;
- a feed-back loop for reconstructing the time-domain adaptive filter, including:
- a time-domain estimator for an acoustic transfer function, the acoustic transfer function modelling conversion of an electrical signal into an acoustic domain signal, the time-domain estimator being applied to the time-domain output signal,
- a signal path for providing the reference signal in the time-domain in response to the primary signal in the time-domain and the estimated time-domain output signal,
- a subband estimator for the acoustic transfer function, the subband estimator being applied to the plurality of subband reference signals, and
- an adjustor for adjusting a subband adaptive filter in response to the plurality of subband primary signals and the plurality of estimated reference signal, and
- a synthesis filterbank for synthesizing the time-domain adaptive filter from the subband adaptive filter.
6 more elements
A system for active noise cancellation, comprising:
- an analog active noise cancellation (ANC) system for performing an active noise cancellation to a primary signal in a time-domain, the primary signal being associated with an acoustic signal and comprising noise;
- a first over-sampled analysis filterbank for transferring a reference signal in the time-domain into a plurality of subband reference signals in a frequency-domain, the reference signal in the time-domain being associated with the noise;
- a second over-sampled analysis filterbank for transferring the primary signal in the time-domain into a plurality of subband primary signals in the frequency-domain;
- a time-domain adaptive filter for providing a time-domain output signal in response to the reference signal in the time-domain;
- a subband processing module for processing the plurality of subband reference signals, the plurality of subband primary signals or a combination thereof, including detecting the analog ANC system at brink of instability, and adjusting one or more parameters of the analog ANC system based on the processing;
- the subband processing module comprising:
- a subband estimator for estimating a subband acoustic transfer function, the subband acoustic transfer function modelling conversion of an electrical signal into an acoustic domain signal, the subband estimator being applied to the plurality of subband reference signals;
- a subband adaptive filter for providing a plurality of subband output signals in response to the plurality of subband reference signals;
- an adjustor for adjusting the subband adaptive filter in response to the plurality of subband primary signals and the plurality of estimated subband reference signals;
- an over-sampled synthesis filterbank for synthesizing the time-domain adaptive filter from the subband adaptive filter.
7 more elements
Dependencies are inferred from the claim text.