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Off-line path modeling circuitry and method for off-line feedback path modeling and off-line secondary path modeling

  • US 5,991,418 A
  • Filed: 12/17/1997
  • Issued: 11/23/1999
  • Est. Priority Date: 12/17/1996
  • Status: Expired due to Term
First Claim
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1. An off-line modeling system for modeling a feedback path and a secondary path, the off-line modeling system comprising:

  • a reference sensor operable to receive a noise signal and a feedback signal and to generate a primary signal in response;

    a secondary source operable to receive a modeling signal and to provide the modeling signal through the feedback path and the secondary path;

    an error sensor operable to receive a residual signal and to generate an error signal in response; and

    an off-line modeling circuitry for modeling the feedback path and the secondary path including;

    a modeling signal generator operable to generate the modeling signal,a feedback path signal discrimination circuitry operable to receive the primary signal and to generate a modified modeling feedback signal, said feedback path signal discrimination circuitry including;

    a decorrelation delay unit operable to delay the primary signal and to generate a delayed output signal that corresponds to a delayed primary signal,an adaptive discrimination filter operable to receive the delayed output signal and the modified modeling feedback signal and to filter the delayed output signal to generate a predicted noise signal, anda first summing junction operable to subtract the predicted noise signal from the primary signal to generate the modified modeling feedback signal,a feedback path modeling adaptive filter operable to receive the modeling signal and a feedback path modeling error signal and to filter the modeling signal to generate a first output signal, the feedback path modeling adaptive filter operable to calculate feedback neutralization filter taps,a second summing junction operable to subtract the first output signal from the modified modeling feedback signal to generate the feedback path modeling error signal which is provided to a first adaptive algorithm used by the feedback path modeling adaptive filter,a secondary path signal discrimination circuitry operable to receive the error signal and to generate a modified modeling secondary path signal,a secondary path modeling adaptive filter operable to receive the modeling signal and a secondary path modeling error signal and to filter the modeling signal to generate a second output signal, the secondary path modeling adaptive filter operable to calculate secondary path compensation filter taps, anda third summing junction operable to subtract the second output signal from the modified modeling secondary path signal to generate the secondary path modeling error signal which is provided to a second adaptive algorithm used by the secondary path modeling adaptive filter.

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