US 12,456,447 B2
Tools and methods for designing filters for use in active noise cancelling systems
Paul Shields, Dunblane (GB); Wessel Harm Lubberhuizen, Hengelo (NL); and Fotios Kontomichos, Patras (GR)
Assigned to Renesas Design Netherlands B.V., 's-Hertogenbosch (NL)
Filed by Renesas Design Netherlands B.V., 's-Hertogenbosch (NL)
Filed on Dec. 15, 2022, as Appl. No. 18/066,332.
Prior Publication US 2024/0203391 A1, Jun. 20, 2024
Int. Cl. G10K 11/178 (2006.01)
CPC G10K 11/17817 (2018.01) [G10K 11/17823 (2018.01); G10K 11/17825 (2018.01); G10K 11/17881 (2018.01); G10K 2210/3022 (2013.01); G10K 2210/3026 (2013.01); G10K 2210/3027 (2013.01); G10K 2210/3028 (2013.01); G10K 2210/3055 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A computer-implemented method of automated filter design comprising designing a feedback filter for an active noise cancelling system;
wherein designing the feedback filter comprises determining a filter transfer function of the feedback filter;
wherein the filter transfer function is determined using an optimization method;
wherein determining the filter transfer function comprises:
defining an error function that is dependent on an open loop design target and target transfer function, the open loop design target being dependent on the filter transfer function; and
applying the optimization method using the error function to determine filter expression for the filter transfer function that either:
i) reduces the error function to a sufficiently small value that is indicative of the open loop design target being sufficiently close to the target transfer function; and/or
ii) minimizes the error function.