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Active noise control system and method for on-line feedback path modeling and on-line secondary path modeling

  • US 5,940,519 A
  • Filed: 12/17/1997
  • Issued: 08/17/1999
  • Est. Priority Date: 12/17/1996
  • Status: Expired due to Term
First Claim
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1. An active noise control system for generating an anti-noise signal to attenuate a noise signal provided through a media, the active noise control system performing on-line feedback path modeling and on-line secondary path modeling, the active noise control system comprising:

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

    a secondary source operable to receive a secondary signal and to generate a corresponding anti-noise signal that is provided to the media to attenuate the noise signal;

    an error sensor operable to receive a residual signal that is the combination of the noise signal and the anti-noise signal as received at the error sensor, and to generate an error signal in response; and

    an active noise control system controller operable to receive the primary signal and the error signal and to generate the secondary signal while performing on-line feedback path modeling and on-line secondary path modeling, the active noise control system controller including;

    a modeling signal generator operable to generate a modeling signal,an on-line 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 on-line feedback path modeling adaptive filter operable to generate filter taps to minimize the feedback path modeling error signal,a feedback signal discrimination circuitry operable to receive a feedback neutralized primary signal and to generate a modified modeling feedback signal,a first summing junction operable to subtract the first output signal of the on-line feedback path modeling adaptive filter from the modified modeling feedback signal to generate the feedback path modeling error signal used by the on-line feedback path modeling adaptive filter,a feedback neutralization filter operable to receive and use the filter taps generated by the on-line feedback path modeling adaptive filter and to filter a generated secondary signal to generate an anti-noise feedback component of the primary signal,a second summing junction operable to subtract the anti-noise feedback component from the primary signal to generate the feedback neutralized primary signal,an on-line 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 on-line secondary path modeling adaptive filter operable to generate filter taps to minimize the secondary path modeling error signal,a secondary path signal discrimination circuitry operable to receive the error signal and to generate a modified modeling secondary path signal,a third summing signal junction operable to subtract the second output signal of the on-line secondary path modeling adaptive filter from the modified modeling secondary path signal to generate the secondary path modeling error signal used by the on-line secondary path modeling adaptive filter,a secondary path compensation filter operable to receive and use the filter taps generated by the on-line secondary path modeling adaptive filter and to filter the feedback neutralized primary signal to generate a secondary path compensated primary signal,a system adaptive filter operable to receive the feedback neutralized primary signal, the error signal, and the secondary path compensated primary signal and to filter the feedback neutralized primary signal to generate a generated secondary signal, anda fourth summing junction operable to combine the generated secondary signal with the modeling signal to generate the secondary signal.

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