Digital filter modeling for active noise cancellation

Details Digital filter modeling for active noise cancellation Digital filter modeling for active noise cancellation

2002-12-09

2008-11-11

Mei, Xu (Department: 2615)

Electrical audio signal processing systems and devices

Acoustical noise or sound cancellation

C381S071900

Reexamination Certificate

active

07450725

ABSTRACT:
An active noise cancellation system (20) includes digital modeling of the physical path that is compensated for using a digital filter (34). An initial estimate of the time domain response of the system (20) is achieved using inverse time domain convolution to determine the signal values of a speaker (24) and a microphone (26) in the system. The estimated time domain response of the system is used to determine the initial estimate of the modeled digital filter. In one example, the initial estimate is then used as part of a convergence technique, such as a least mean squares algorithm. In another example, a plurality of initial estimates are determined and then averaged to arrive at the filter value used during noise cancellation.

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Patents Act 1977: Search Report under Section 17 Date of Search: Mar. 27, 2003.

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