Electrical audio signal processing systems and devices – Acoustical noise or sound cancellation – Counterwave generation control path
Reexamination Certificate
2004-05-27
2008-03-04
Chin, Vivian (Department: 2615)
Electrical audio signal processing systems and devices
Acoustical noise or sound cancellation
Counterwave generation control path
C381S086000, C381S094100, C381S071800
Reexamination Certificate
active
07340065
ABSTRACT:
An active noise control system is provided which cancels a noise using a sound radiated from a speaker driven by an output from an adaptive notch filter. The system employs output signals from an adder or simulation cosine-wave and sine-wave signals, an error signal or an output signal from a microphone, and a compensated signal from the adder or a signal available for acoustically transferring an output from the adaptive notch filter to the microphone in accordance with initial transfer characteristics to update the filter coefficient of the adaptive notch filter. This configuration allows the system to operate with stability even when the acoustic transfer characteristics vary with time or under circumstances where there exists a significant amount of incoming external noises. The system also prevents overcompensation for a noise at the ears of a passenger in a vehicle, thereby proving an ideal noise reduction effect.
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Inoue Toshio
Nakamura Yoshio
Onishi Masahide
Takahashi Akira
Chin Vivian
Honda Giken Kogyo Kabushiki Kaisha
Jordan and Hamburg LLP
Tran Con P.
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