The Design And Realization Of A Reconfigurable Digital Filter-bank For Hearing-aid Systems Based On FPGA

Hearing loss has become one of the most common diseases which have an impact on people’s lives recently. The most effective way to compensate hearing loss is using the digital hearing aids. The digital hearing aids amplify sound wave selectively and then transmit the processed signal to human ear. The decomposition of sounds is done by a filter-bank. People have done a lot of research on the digital filter-bank of this use. Some research is based on the uniform filter-bank while others are based on the non-uniform filter-bank. Both ways just use a single frequency division plan, thus cannot make the best sound compensation strategy based on the hearing loss characteristics of the patients. Therefore, the design of a filter-bank whose sub-band can be adjusted case by case is of great practical significance.Since the designed system is a FIR system, we paid much attention to the theory of FIR filters, including the linear phase characteristics, the design methods and the realization in Matlab. All above help us design the prototype filters which will be used in the design process of the re-configurable filter-bank.Secondly, this paper illustrates how the re-configurable filter-bank works. We can change the sub-bands of the proposed filter-bank by changing some control parameters without changing the structure of the filter-bank.Thirdly, the knowledge relevant to FPGA is introduced, including the VHDL programming language and the Modelsim simulation software.Last but not the least, this paper discusses the FPGA implementation of the re-configurable filter-bank. The programming language is VHDL and the development environment is Quartus Ⅱ. We use Modelsim, combined with Matlab, to verify the correction of the design.