Patent ID: 7103188
Filing Date: 2006-09-05
Classification: G10K,H04R

Abstract:
1. An active noise canceling system comprising: a sound generator, responsive to drive signals applied thereto, for generating an anti-noise field; a noise cancellation processor, for generating the drive signals to the sound generator; a first sound sensor disposed within said anti-noise field to generate a residual signal indicative of the sum of ambient sounds and anti-noise impinging on the sensor, wherein said noise cancellation processor processes the residual signal to form a component of the anti-noise field; and means for generating indicia of the level of ambient noise and responsively varying a transfer function of the system in response to said indicia of amplitude of ambient noise such that a gain of the transfer function of the system is decreased in response to a decrease in said indicia of amplitude of ambient noise, wherein the transfer function comprises a ratio of an output signal of the noise cancellation processor to at least the residual signal.