Importance

Loading Importance Indicators...

Abstract

An active acoustic attenuation system prevents overdriving of the canceling output transducer or speaker (14) by shunting at least part of the correction signal (46) to a parallel shunt path (306) and away from the output transducer (14) Variable gains (308 and 310) are provided in the shunt path (306) and the input to the output transducer (14) for varying the ratio between the part of the correction signal (46) supplied to the output transducer (14) and the part of the correction signal (46) shunted to the shunt path (306). A first adaptive filter model (40) has an error input (202) from the error signal and outputs the correction signal (46). A second adaptive filter model (142) models the output transducer (14) and the error path (56) between the output transducer (14) and the error transducer (16). A copy (312) of the second model (142) has an input from the output (46) of the first model (40), and the output of the copy (312) is summed with the error signal (44) and the resultant sum is supplied to the error input (202) of the first model (40), such that the shunt path (306) is provided through the model copy (312).

Loading the Abstract Image...

First Claim