Procedure for the steady-state verification of modulation-based noise reduction systems in hearing instruments

Abstract

Hearing instrument verification involves measuring the performance of modulation-based noise reduction systems.The article proposes a systematic procedure for their verification. The procedure has the potential for application inthe verification of other signal processing systems, because it is independent of the hearing instrument domain. Itskey concept, the separation of abstract and concrete design of test signals, has been adopted from the embeddedsystems domain. Specifically for modulation-based noise reduction systems in hearing instruments, the articleshows a complete implementation of the verification procedure, proposing improvements of existingmeasurement techniques. To fully cover the verification procedure, a new measurement approach based onmaximum length sequences and DFT processing is introduced, revisiting concepts of system identification thatcame up in the 1970s. These can easily be used with the computational resources of today’s microcomputers.Sample measurements with existing hearing instruments demonstrate the verification procedure with differentmeasurement techniques.