Active noise cancellation system with wind noise reduction

摘要

Active Noise Cancellation (ANC) system and method comprising an ANC signal which is generated by a signal processor in response to an ambient noise signal, comprising detecting the wind amplitude, controlling the cut-off frequency of a high pass filter (HPF) of the signal processor based on the wind amplitude, and controlling the gain of the signal processor based on the output of a low pass filter (LPF). The HPF cut-off frequency may be increased / reduced when the wind strength is above / below a first threshold. The ANC gain may be reduced / increased when the wind exceeds a second threshold for a time that is greater / lower than a predetermined fraction of a time window. The second threshold may be higher than the first threshold. Instantaneous wind measurements based on a comparison between a cross-correlation between two microphone signals may be smoothed to form the detected amplitude by comparing with previous values and using attack or decay coefficients. The ANC system may be incorporated into earphones or a mobile phone and does not generate a signal that would magnify the wind noise heard by the user.