tailieunhanh - Báo cáo hóa học: " Procedure for the steady-state verification of modulation-based noise reduction systems in hearing instruments"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Procedure for the steady-state verification of modulation-based noise reduction systems in hearing instruments | Lamm et al. EURASIP Journal on Advances in Signal Processing 2011 2011 100 http content 2011 1 100 o EURASIP Journal on Advances in Signal Processing a SpringerOpen Journal RESEARCH Open Access Procedure for the steady-state verification of modulation-based noise reduction systems in hearing instruments Jesko G Lamm Anna K Berg Christian M Kunzler Bernhard Kuenzle and Christian G Gluck 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 in the verification of other signal processing systems because it is independent of the hearing instrument domain. Its key concept the separation of abstract and concrete design of test signals has been adopted from the embedded systems domain. Specifically for modulation-based noise reduction systems in hearing instruments the article shows a complete implementation of the verification procedure proposing improvements of existing measurement techniques. To fully cover the verification procedure a new measurement approach based on maximum length sequences and DFT processing is introduced revisiting concepts of system identification that came 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 different measurement techniques. 1 Introduction A hearing instrument should assist its user by amplifying sound with a certain gain but can also cause discomfort in noisy environments. Therefore its noise reduction subsystem should reduce the hearing instrument s gain while noise is present - usually dependent on frequency in different subbands. To preserve speech understanding the noise reduction should avoid gain reduction in those subbands that contain speech. Based on the observation that