Abstract: The technology described this document can be embodied in a method that includes receiving an error signal captured using a microphone, the error signal representing a difference between the sinusoidal component of a noise signal and an output of an acoustic transducer. The output of the acoustic transducer is configured to reduce the effects of the sinusoidal component of the noise signal. The method includes processing the error signal to compensate for effects due to a signal path between the acoustic transducer and the microphone, and determining a current estimate of one or more first parameters of the error signal. Based on such parameters, a current estimate of a time-varying step size associated with an adaptive process is determined, and based on the current estimate of the time-varying step size, a driver signal configured to change the output of the acoustic transducer is generated.

Abstract: A method and system for a noise cancellation comprises an amplifier in communication with three or more speakers disposed in an area. A system controller produces a driver signal for each of the speakers in response to a signal from at least one microphone detecting sound in the area and communicates the driver signals to the amplifier. The amplifier drives each speaker with the driver signal produced for that speaker. In response to the driver signals, the speakers emit sound having a magnitude and phase that combine to attenuate a noise field in the area.

Abstract: A method and system for a noise cancellation comprises an amplifier in communication with the three or more speakers disposed in an area. A system controller produces a driver signal for each of the speakers in response to a signal from at least one microphone detecting sound in the area and communicates the driver signals to the amplifier. The amplifier drives each speaker with the driver signal produced for that speaker. In response to the driver signals, the speakers emit sound that combined produces a substantially uniform sound pressure field for a particular zone within the area. The substantially uniform sound pressure field produced by the speakers has a magnitude and phase adapted to attenuate a noise field in the area corresponding to the sound detected by the at least one microphone.

Abstract: A method and system for a noise cancellation comprises an amplifier in communication with the three or more speakers disposed in an area. A system controller produces a driver signal for each of the speakers in response to a signal from at least one microphone detecting sound in the area and communicates the driver signals to the amplifier. The amplifier drives each speaker with the driver signal produced for that speaker. In response to the driver signals, the speakers emit sound that combined produces a substantially uniform sound pressure field for a particular zone within the area. The substantially uniform sound pressure field produced by the speakers has a magnitude and phase adapted to attenuate a noise field in the area corresponding to the sound detected by the at least one microphone.

Abstract: A noise cancellation method and system comprises a system controller that produces a command signal in response to a signal from at least one microphone detecting sound in an area. The system controller includes an arrayed speaker controller for producing a driver signal for each speaker in response to the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone. The system controller includes an in-phase speaker controller for producing a common in-phase driver signal for all speakers in response to the command signal and a signal director module for proportioning the command signal between the arrayed and in-phase speaker controllers in response to a magnitude of voltage associated with driving the speakers in accordance with the command signal.

Abstract: A noise cancellation method and system comprises a system controller that produces a command signal in response to a signal from at least one microphone detecting sound in an area. The system controller includes an arrayed speaker controller for producing a driver signal for each speaker in response to the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone. The system controller includes an in-phase speaker controller for producing a common in-phase driver signal for all speakers in response to the command signal and a signal director module for proportioning the command signal between the arrayed and in-phase speaker controllers in response to a magnitude of voltage associated with driving the speakers in accordance with the command signal.

Abstract: A method and system for attenuating noise comprises identifying a location in an area at which sound emitted from one or more speakers has acoustic characteristics that are substantially similar in measure to corresponding acoustic characteristics of the emitted sound at a location approximated to be near an ear of an occupant of the area. A microphone, which may be a virtual microphone, is disposed at the identified location. The microphone detects sound at the identified location. In response to the sound detected by the microphone, the one or more speakers emit a noise-canceling audio signal adapted to attenuate one or more frequencies in the sound detected by the microphone.

Abstract: A method for automatically switching an audio source includes the steps of receiving an audio signal from a video display device, and receiving a digital audio signal from one of a plurality of audio/video source devices which each can supply audio and video information to the video display device. The digital audio signal is compared with the audio signal from the video display device. The digital audio signal is output to a supplemental audio system of the video display device when the comparing step indicates that the digital audio signal and the audio signal from the video display device contain substantially similar audio programs.

Abstract: An active wheel damper. An active suspension damps vertical displacement of an unsprung mass in a frequency range and reduces vertical displacement of a sprung mass in another frequency range.

Abstract: An active wheel damper. An active suspension damps vertical displacement of an unsprung mass in a frequency range and reduces vertical displacement of a sprung mass in another frequency range.

Abstract: An active suspension for a vehicle includes an actuator which incorporates a first rotary motor, a second rotary motor, and a transmission coupled to the first and second rotary motors to convert rotary motion to linear motion. A compensation force is determined to compensate for the rotary inertia of the system. A force feedback loop can be employed to reduce the error between the output force of the actuator and a force command supplied by an active suspension system controller.

Abstract: A method for automatically switching an audio source includes the steps of receiving an audio signal from a video display device, and receiving a digital audio signal from one of a plurality of audio/video source devices which each can supply audio and video information to the video display device. The digital audio signal is compared with the audio signal from the video display device. The digital audio signal is output to a supplemental audio system of the video display device when the comparing step indicates that the digital audio signal and the audio signal from the video display device contain substantially similar audio programs.

Abstract: A system for modulating and demodulating signals that provides a new class of signal modulators and their corresponding demodulators. The modulation scheme embeds in an information signal a carrier signal by modulating the oscillatory rate of the carrier signal. The invention generalizes the possible carrier signals to any signal which can be generated by a dynamical system that have a known exponentially convergent observer, as in certain chaotic systems.

Abstract: A system for modulating and demodulating signals that provides a new class of signal modulators and their corresponding demodulators. The modulation scheme embeds in an information signal a carrier signal by modulating the oscillatory rate of the carrier signal. The invention generalizes the possible carrier signals to any signal which can be generated by a dynamical system that have a known exponentially convergent observer, as in certain chaotic systems.