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Adaptive noise canceling system and FM radio communication receiver using said system

  • US 5,710,996 A
  • Filed: 05/26/1995
  • Issued: 01/20/1998
  • Est. Priority Date: 09/30/1994
  • Status: Expired due to Term
First Claim
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1. A frequency modulation radio communication receiver using an adaptive noise canceling system for improving clarity of an output signal, said receiver comprising:

  • a radio receiving means for receiving a radio frequency signal;

    a demodulating means for demodulating the radio frequency signal, an output of said demodulating means being a signal X(j);

    an adaptive noise canceling system for improving a S/N ratio and clarity of an output signal Z(j);

    an audio frequency signal outputting means for outputting an audio signal of the output signal Z(j) of said adaptive noise canceling system;

    wherein said adaptive noise canceling system includes;

    a delaying means for delaying the demodulated signal X(j) by a fixed time delay δ

    , an output of said delaying means being a signal D(j);

    a filtering means, having as an input the signal D(j), for filtering the delayed signal D(j), an output of said filtering means comprising a signal Y(j);

    a subtracting means, having as inputs the signals X(j) and Y(j), for subtracting the signal Y(j) from the signal X(j), an output of said subtracting means being an error signal ε

    (j);

    a coefficients adjusting means, having as an input the error signal ε

    (j), for adaptively adjusting coefficients of said filtering means using a least-means-square (LMS) algorithm, an output of said coefficients adjusting means being the coefficients of said filtering means;

    a level adjusting means, having as an input the error signal ε

    (j), for adjusting a level of the error signal ε

    (j), an output of said level adjusting means being a signal ε

    '"'"'(j);

    an adding means for adding the level adjusted signal ε

    '"'"'(j) to the output signal Y(j) of said filtering means, an output of the adding means being the output signal Z(j).

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