ANC noise active control audio headset with prevention of the effects of a saturation of the feedback microphone signal

摘要

The headset includes an active noise control, with an internal ANC microphone (28) placed inside the acoustic cavity (22) and delivering a signal including an acoustic noise component. A digital signal processor DSP (50) comprises a feedback ANC branch (54) applying a filtering transfer function (54, HFB2) to the signal delivered by the ANC microphone, and a mixer (60) for mixing the signal of the feedback branch with an audio signal to be reproduced (M). The headset comprises a movement sensor (64) mounted on one of the earphones. The DSP comprises an anti-saturation module (68) for analyzing concurrently i) the signal delivered by the internal microphone (28) and ii) the signal delivered by the movement sensor (64), and verifying whether current characteristics of these signals fulfill or not a set of predetermined criteria. Upstream from the feedback ANC filter (54), an anti-saturation filter (70, HFB1) is selectively switched as a function of the result of this verification. The filtering of an equalization branch (58, HEQ2) of the signal to be reproduced (M) is also modified by a similar anti-saturation filter (72, HEQ1).

主权项

1. An audio headset, comprising:
two earphones (10) each including a transducer (18) for the sound reproduction of an audio signal to be reproduced, said transducer being housed in an ear acoustic cavity (22); at least one microphone adapted to deliver a picked-up signal including an acoustic noise component; a movement sensor (64) mounted on at least one of the earphones and adapted to deliver an accelerometer signal; and a digital signal processor, DSP, (50) comprising:
a mixer, receiving as an input a signal coming from the microphone as well as said audio signal to be reproduced, and delivering as an output a signal adapted to pilot the transducer (18); andan anti-saturation module adapted to analyse concurrently i) the microphone signal delivered by the microphone and ii) the accelerometer signal delivered by the movement sensor (64), and to verify whether current characteristics of these microphone and accelerometer signals fulfil or not a first set of predetermined criteria,characterized in that:
the headset comprises an ANC active noise control system; the microphone is an internal ANC microphone (28) placed inside the acoustic cavity (22); the DSP (50) comprises:
a closed-loop feedback branch (36), comprising a feedback ANC filter (54) adapted to apply a filtering transfer function (HFB) to the signal picked up by the internal ANC microphone (28); andthe mixer, which receive as an input the signal delivered by the feedback branch at the output of the feedback ANC filter (54) as well as said audio signal to be reproduced, and deliver as an output said signal adapted to pilot the transducer (18); and the DSP further comprises a prevention module for preventing the effects on the feedback branch of a saturation of the signal delivered by the internal microphone (28), comprising:
the anti-saturation module adapted to analyse concurrently i) the microphone signal delivered by the microphone (28) and ii) the accelerometer signal delivered by the movement sensor (64), and to verify whether current characteristics of these microphone and accelerometer signal fulfil or not a first set of predetermined criteria; andin the feedback branch upstream from the feedback ANC filter (54), a feedback anti-saturation filter (70) selectively switchable as a function of the result of the verification of the first set of criteria.