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Microphone device and audio player

  • US 20040185804A1
  • Filed: 11/18/2003
  • Published: 09/23/2004
  • Est. Priority Date: 11/18/2002
  • Status: Active Grant
First Claim
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1. A microphone device which detects a target sound coming from a direction of the target sound, comprising:

  • a signal generating section for generating a main signal indicative of a result obtained through detection with a sensitivity in the direction of the target sound and a noise reference signal indicative of a result obtained through detection with a sensitivity higher in another direction than in the direction of the target sound;

    a determining section for determining whether a level ratio indicative of a ratio of a level of the main signal to the noise reference signal generated by the signal generating section is larger than a predetermined value;

    an adaptive filter section for generating a signal indicative of a signal component of the target sound included in the noise reference signal generated by the signal generating section by performing, by an adaptive filter included in the adaptive filter section, a filtering process on the main signal generated by the signal generating section, and for learning a filter coefficient only when the determining section determines that the level ratio is larger than the predetermined value;

    a subtracting section for subtracting the signal generated by the adaptive filter section from the noise reference signal generated by the signal generating section; and

    a noise suppressing section for suppressing a signal component of noise included in the main signal by using the main signal and the noise reference signal after subtraction by the subtracting section.

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