AUDIO HEAD SET HAVING NON-ADAPTIVE ACTIVE NOISE CONTROL FUNCTION FOR LISTENING AUDIO SOUND SOURCE AND/OR 'HANDS-FREE' TELEPHONE FUNCTION

摘要

PROBLEM TO BE SOLVED: To deal with the risk of instability, by increasing the gain and phase margin in a non-adaptive ANC system.;SOLUTION: The active noise control of a headset includes, in parallel, a feedforward band-pass filter 32 receiving a signal from an external microphone 28, a feedback band-pass filter 42 receiving an error signal e transmitted by an internal microphone 36 as an input, and a stabilizer band-pass filter 44 locally increasing the phase of transfer function of a feedback filter in an instability band, especially in a water bed effect band around 1 kHz. An adder circuit 46 sends a weighted linear combination of signals being sent by these filters and an audio signal S to be reproduced. The control is non-adaptive, and the parameters of the filters 32, 42, 44 are static.;COPYRIGHT: (C)2013,JPO&INPIT