Patent ID: 7539613
Filing Date: 2009-05-26
Classification: G10L

Abstract:
1. A band recovering device for recovering frequency components lying in a frequency band lost due to band-limitation of a sound signal, comprising: a peak-limiting amplifier configured to amplify an input narrow-band voice signal while preventing a resulting amplified voice signal from exceeding a predetermined maximum amplitude; a peak-limitation detector configured to detect whether or not a level of the amplified voice signal output from said peak-limiting amplifier is substantially coincident with the maximum amplitude; an amplification controller configured to increase at least either one of an amplification factor and an amount of amplification of said peak-limiting amplifier until the level of the amplified voice signal output from said peak-limitation detector is substantially coincident with the maximum amplitude; and a band recovering circuit configured to use a voice signal component of the amplified voice signal output from said peak-limiting amplifier and the input narrow-band voice signal to produce a band-recovered voice signal including the frequency components lying in the frequency band lost, the voice signal component being in frequency higher than the input narrow-band voice signal.