The invention provides a digital hearing-aid unequal-width sub-band
automatic gain control method. The method includes: designing an unequal-width analysis
filter bank according to
human ear auditory characteristics, conducting segment
processing to input acoustical signals, filtering each segment acoustical
signal by using the analysis
filter bank to obtain signals of various sub-bands, counting input
signal sound pressure level inside the various sub-bands, conducting sub-band automatic
gain adjustment according to the sub-band
signal sound pressure level, finally using a synthesizing
filter bank to synthesize adjusted sub-band signals to obtain
system output signals. According to the digital hearing-aid unequal-width sub-band
automatic gain control method,
noise and voice signals are isolated out through the sub-band filter
bank, and thus the gains of
noise frequency ranges and the voice signals are respectively controlled, and the roles of
noise suppression and signal-to-noise ratio improvement are played. Compared with a traditional equal-width sub-band filter
bank partition method, an unequal-width filter
bank sub-band partition method used by the digital hearing-aid unequal-width sub-band
automatic gain control method coincides with the
human ear auditory characteristics. On the premise of obtaining the same effect, the amount of sub-bands need parting and the calculated amount are reduced. In addition, the digital hearing-aid unequal-width sub-band automatic
gain control method is achieved totally by a
software program with no need of adding an additional hardware circuit, thereby saving the cost, weight and size of a product.