US 11,770,114 B2
Subband adaptive filter for systems with partially acausal transfer functions
Eric Raczka Bernstein, Cambridge, MA (US); Wade P. Torres, Attleboro, MA (US); and Ankita D. Jain, Westborough, MA (US)
Assigned to Bose Corporation, Framingham, MA (US)
Filed by Bose Corporation, Framingham, MA (US)
Filed on Feb. 5, 2021, as Appl. No. 17/168,676.
Application 17/168,676 is a continuation of application No. 16/369,897, filed on Mar. 29, 2019, granted, now 10,917,074.
Prior Publication US 2021/0167757 A1, Jun. 3, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H03H 21/00 (2006.01); G10K 11/178 (2006.01); H04R 3/00 (2006.01)
CPC H03H 21/0012 (2013.01) [G10K 11/17817 (2018.01); H04R 3/005 (2013.01); H03H 2021/0078 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method comprising:
receiving, at one or more processing devices, an input signal;
receiving, at the one or more processing devices, a feedback signal;
generating, based on the input signal and the feedback signal, an updated set of filter coefficients of an adaptive filter, wherein generating the updated set of filter coefficients of the adaptive filter comprises:
determining, for each of multiple frequency subbands of the input signal, one or more coefficients of a corresponding subband adaptive filter, and
combining one or more coefficients of multiple subband adaptive filters to generate the updated set of filter coefficients of the adaptive filter,
wherein determining the one or more coefficients of the corresponding subband adaptive filter comprises:
(a) obtaining a precomputed set of filter coefficients of the adaptive filter, and
(b) selecting a subset of the precomputed set of filter coefficients of the adaptive filter, wherein a number of coefficients in the subset is less than a number of the precomputed set of filter coefficients of the adaptive filter, and wherein selecting the subset of the precomputed set of filter coefficients of the adaptive filter comprises selecting the subset based on a correspondence of the subset to a causal relationship between the input signal and another signal traversing a path represented by a transfer function of the adaptive filter; and
processing a portion of the input signal using the updated set of filter coefficients of the adaptive filter to generate an output that destructively interferes with the another signal traversing the path represented by the transfer function.