Patent ID: 7765099

Claim:
A band recovering device for receiving a narrow-band signal with a frequency band lost due to band-limitation of a sound signal, and recovering frequency components lying in the lost frequency band, comprising: an amplitude limiter having a restriction value controllable by a control signal, and configured to limit a peak value of the input narrow-band signal using the restriction value, the amplitude limiter generating an output signal with a peak value; a detector configured to detect whether the peak value of the output signal is limited by the restriction value, and to produce a detection output signal based on a result of the detection; an amplitude-limit controller configured to produce the control signal to decrease the restriction value when the detection output signal indicates that the peak value of the output signal of the amplitude limiter is limited by the restriction value; and a band recovering circuit configured to generate, based on the output signal of said amplitude limiter and the input narrow-band signal, a band-recovered signal including the frequency components lying in the lost frequency band.