Abstract: Noise cancellation systems and methods are provided that receive a reference signal representative of a noise to be reduced and provide a noise cancellation signal based upon the reference signal. Some examples include a feedback signal representative of a residual noise in the environment. At least one of the reference signal, the noise cancellation signal, or the feedback signal is filtered to remove components based upon a rotational rate of a rotating equipment associated with the environment, such as an engine of a vehicle. Accordingly, the noise cancellation system may not interfere with sounds related to the engine.

Abstract: A system and method for reducing harmonic noise caused by two or more noise sources by causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each noise source. Each noise canceller includes a harmonic sine wave generator that generates an output sine wave. Each noise canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the noise sources. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: A system and method for reducing harmonic noise caused by two or more noise sources by causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each noise source. Each noise canceller includes a harmonic sine wave generator that generates an output sine wave. Each noise canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the noise sources. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: An engine harmonic enhancement system. The EHE system uses multiple parameters, such as engine load, gear, number of cylinders operating, and transmission ratio, to determine EHE gains to determine EHE gain. The EHE system determines a separate EHE gain for each harmonic.

Abstract: A system and method for reducing harmonic noise caused by two or more noise sources by causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each noise source. Each noise canceller includes a harmonic sine wave generator that generates an output sine wave. Each noise canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the noise sources. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: An engine harmonic enhancement system. The EHE system uses multiple parameters, such as engine load, gear, number of cylinders operating, and transmission ratio, to determine EHE gains to determine EHE gain. The EHE system determines a separate EHE gain for each harmonic.

Abstract: A system and method for reducing noise caused by two or more rotating devices by taking in input signals with frequencies that are related to the rotation rates of the rotating devices, and causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each rotating device. Each noise canceller includes a harmonic frequency computer that computes a harmonic frequency and provides the harmonic frequency to a harmonic sine wave generator that generates an output sine wave. Each nose canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the rotating devices. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: A system and method for reducing harmonic noise caused by two or more noise sources by causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each noise source. Each noise canceller includes a harmonic sine wave generator that generates an output sine wave. Each noise canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the noise sources. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: A system and method for reducing noise caused by two or more rotating devices by taking in input signals with frequencies that are related to the rotation rates of the rotating devices, and causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each rotating device. Each noise canceller includes a harmonic frequency computer that computes a harmonic frequency and provides the harmonic frequency to a harmonic sine wave generator that generates an output sine wave. Each nose canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the rotating devices. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: An engine harmonic enhancement system. The EHE system uses multiple parameters, such as engine load, gear, number of cylinders operating, and transmission ratio, to determine EHE gains to determine EHE gain. The EHE system determines a separate EHE gain for each harmonic.