公开(公告)号：CA1308362C

公开(公告)日：1992-10-06

申请号：CA612604

申请日：1989-09-22

Applicant: MOTOROLA INC

Inventor： VILMUR RICHARD J ,  BARLO JOSEPH J ,  GERSON IRA A ,  LINDSLEY BRETT L

IPC: H04B1/10 ,  H04B15/00

Abstract: An improved noise suppression system (800) is disclosed which performs speech quality enhancement upon the speech-plus-noise signal available at the input (205) to generate a clean speech signal at the output (265) by spectral gain modification. The improvements of the present invention include the addition of a signal-to-noise ratio (SNR) threshold mechanism (830) to reduce background noise flutter by offsetting the gain rise of the gain tables until a certain SNR threshold is reached, the use of a voice metric calculator (810) to produce more accurate background noise estimates via performing the update decision based on the overall voice-like characteristics in the channels and the time interval since the last update, and the use of a channel SNR modifier (820) to provide immunity to narrowband noise bursts through modification of the SNR estimates based on the voice metric calculation and the channel energies.