公开(公告)号：US09614486B1

公开(公告)日：2017-04-04

申请号：US14984770

申请日：2015-12-30

Applicant: Amazon Technologies, Inc.

Inventor： Jun Yang ,  Philip Ryan Hilmes ,  Colin McEnroe ,  Chad G Seguin

IPC: H03G3/00 ,  H03G3/30

CPC classification number: H03G3/3005 ,  H03G3/3089 ,  H03G7/002 ,  H03G7/007

Abstract: A gain control system is responsive to a user gain setting and to an effective signal level to calculate and adaptively vary an output gain to avoid output clipping. The effective signal level is calculated by smoothing the energy of an input audio signal in accordance with selected attenuation factors. In times during which fast transient sounds are occurring, attenuation factors corresponding to relatively low levels of attenuation are selected. In times during which fast transient sounds are not detected, attenuation factors corresponding to relatively higher levels of attenuation are selected. The effective signal level is held at a constant level during periods of silence in order to avoid increasing the output gain during these periods. The output gain is calculated based on a comparison of the effective signal level to a compression threshold.