Abstract: A method for measuring performance of a noise cancellation system that is operable to cancel noise is provided. The method includes generating a first model of a target noise. The first model represents the target noise in a form that is received at a location remote from a noise source of the target noise and within a defined environment. The method also includes generating a second model of a cancellation noise. The cancellation noise is configured to at least partially cancel the target noise when combined with the target noise. The second model represents the cancellation noise in a form that is received at the location. The method also includes determining, using the first model and the second model, a cancellation error value indicative of only a portion of the target noise that remains when the target noise and the cancellation noise are combined.

Abstract: A method for detecting failure in a noise cancellation system is provided. The noise cancellation system is operable to at least partially cancel an unwanted noise produced by a noise source. The method includes receiving a cancellation noise signal from the noise cancellation system. The cancellation noise signal represents a cancellation noise that, when combined with a target noise, is operable to at least partially cancel the target noise. The method also includes receiving an error signal approximately representing a portion of the target noise that remains after the cancellation noise and the target noise are combined. The method also includes determining whether the signal level changed or remains unchanged for each of the received cancellation noise signal and the error signal. The method also includes assigning a failure state of the noise cancellation system based on the determination and initiating a remedial measure that corresponds with the assigned failure state.

Abstract: A method for controlling a noise cancellation system having an adaptive control portion is provided. The noise cancellation system is operable to generate a cancellation noise configured to at least partially cancel an unwanted noise in a defined environment. The adaptive control portion is operable to adjust the operation of the noise cancellation system based on a level of unwanted noise that remains when the cancellation noise and the unwanted noise are combined. The method includes receiving an error signal representing a portion of a noise not cancelled by a cancellation noise, where the cancellation noise is generated from the noise cancellation system. The method also includes determining whether the level of the error signal exceeds a first threshold value for a first predetermined period of time. The method also includes calculating a crest factor using the error signal. The method also includes determining whether the crest factor exceeds a second threshold value.

Abstract: A method for detecting failure in a noise cancellation system is provided. The noise cancellation system is operable to at least partially cancel an unwanted noise produced by a noise source. The method includes receiving a cancellation noise signal from the noise cancellation system. The cancellation noise signal represents a cancellation noise that, when combined with a target noise, is operable to at least partially cancel the target noise. The method also includes receiving an error signal approximately representing a portion of the target noise that remains after the cancellation noise and the target noise are combined. The method also includes determining whether the signal level changed or remains unchanged for each of the received cancellation noise signal and the error signal. The method also includes assigning a failure state of the noise cancellation system based on the determination and initiating a remedial measure that corresponds with the assigned failure state.

Abstract: A method for measuring performance of a noise cancellation system that is operable to cancel noise is provided. The method includes generating a first model of a target noise. The first model represents the target noise in a form that is received at a location remote from a noise source of the target noise and within a defined environment. The method also includes generating a second model of a cancellation noise. The cancellation noise is configured to at least partially cancel the target noise when combined with the target noise. The second model represents the cancellation noise in a form that is received at the location. The method also includes determining, using the first model and the second model, a cancellation error value indicative of only a portion of the target noise that remains when the target noise and the cancellation noise are combined.

Abstract: A method for controlling a noise cancellation system having an adaptive control portion is provided. The noise cancellation system is operable to generate a cancellation noise configured to at least partially cancel an unwanted noise in a defined environment. The adaptive control portion is operable to adjust the operation of the noise cancellation system based on a level of unwanted noise that remains when the cancellation noise and the unwanted noise are combined. The method includes receiving an error signal representing a portion of a noise not cancelled by a cancellation noise, where the cancellation noise is generated from the noise cancellation system. The method also includes determining whether the level of the error signal exceeds a first threshold value for a first predetermined period of time. The method also includes calculating a crest factor using the error signal. The method also includes determining whether the crest factor exceeds a second threshold value.

Abstract: A system and method of reducing noise in an enclosure is disclosed. The method includes receiving at least one reference signal; receiving pressure signals from no more than two substantially orthogonally placed pairs of acoustic sensors, where one pair of acoustic sensors is in the x-direction and one pair of acoustic sensors is in the y-direction, and where the acoustic sensors are placed in a plane which is substantially parallel and in proximity to an inner surface of the enclosure; using the pressure signals and the reference signal to generate an output signal to minimize energy density at a location of the acoustic sensors; and sending the output signal to an acoustic actuator.