A DSP implementation of a digital hearing aid with recruitment of loudness compensation and acoustic echo cancellation

This paper describes a DSP implementation of a digital hearing aid realized in the frequency domain that compensates for recruitment of loudness and cancels acoustic echos. In contrast to conventional systems which are based on a noise-probe signal, our echo canceler is adapted using only the available (e.g. speech) input signal. The main problems caused by a nonlinear feedforward filter are discussed using analytical results of the steady state behavior of the closed-loop hearing-aid system. The implemented DSP system is tested with a dummy behind-the-ear (bte) hearing-aid device on a KEMAR-head and results are presented.