Perceptually guided inexact DSP design for power, area efficient hearing aid

Inexact design has been recognized as very viable approach to achieve significant gains in the energy, area and speed efficiencies of digital circuits. By deliberately trading error in return for such these gains, inexact circuits and architectures have been shown to be especially useful in contexts where our senses such as sight and hearing, can compensate for the loss in accuracy. It is therefore important to understand, characterize the manner in which our sensorial systems interact and compensate for the loss in accuracy. Further use this knowledge to optimize and guide the manner in which inexactness is introduced. For the first time, we achieve both of these goals in this paper in the context of human audition-specifically, using the architecture of a hearing-aid and the DSP primitive of an FIR filter as our candidate. Our algorithms for designing an inexact hearing-aid thus use intelligibility as the metric. The resulting inexact FIR filter in the hearing aid is 1.5X or 1.8X more efficient in terms of power-area product while producing 5% or 10% less intelligible speech respectively when compared with the corresponding exact version.¹