Audiogram matching in hearing aid using approximate arithmetic

Filter banks are the major signal processing blocks that dissipate large amount of power in a portable digital hearing aid device. The power consumption can be reduced by replacing the power-hungry multipliers of the filter by power efficient approximate multipliers. This paper illustrates the application of an approximate multiplier for error tolerant hearing aid application. Frequency response masking approach is used for the development of a 10-band non-uniform approximate FIR filter bank with a minimum stop band attenuation of greater than 50 dB. Audiogram matching is done with audiograms of different types of moderate hearing loss and the matching error is computed. Simulation results show that the audiogram matching error falls within +/− 5 dB range.