公开(公告)号：US10038425B1

公开(公告)日：2018-07-31

申请号：US14980577

申请日：2015-12-28

Applicant: Apple Inc.

Inventor： Tzach Zemer ,  Louie Matar ,  Emmanuel Elder

IPC: H03H17/02 ,  G10L21/0264

CPC classification number: H03H17/0223 ,  H03H17/06 ,  H03H17/0664

Abstract: Systems, apparatuses, and methods for implementing a low power filter. A low power filter may generate a reference sum from a reference vector in order to reduce the number of additions which are needed to filter an input sample vector. The reference sum may be used as the starting point for filtering the input sample vector. Then, each input sample of the input sample vector may be compared to a corresponding reference vector sample. If an input sample is different from the corresponding reference vector sample, a correction value based on the corresponding filter coefficient value may be added or subtracted from the reference sum. After all input samples have been compared to corresponding reference vector values and all correction values applied to the reference sum, the modified reference sum may be the output of the filter.