Speech Signal Processing Of A New Piezoelectric Implantable Middle Ear Hearing Device

With the development of society, the number of hearing loss patients increases a lot. All kinds of researches and applications about hearing aid devices have come out. Implantable middle ear hearing devices(IMEHDs), as an effective means, become one of the popular hot researches. At present, the study about IMEHDs has got prominent performance at home and abroad, and has correlative products in market. However, in condition of the overseas high-tech implantable hearing aids hold a dominant status and foreign high-level research, domestic research is still in the initial stage and there is no commercial products coming out temporarily. For this reason, this project is committed to design and study of IMEHDs,and its expectation is exploring an implant system which have high capability-to-quotation and property right.The implantable middle ear hearing device is a system that converts sound to electrical signals, and then the electrical signal drive the piezoelectric vibrator coupled round window membrane. The vibration of the piezoelectric vibrator and the round window membrane make the hearing restored.The device has the following parts in common: a microphone that picks up the sound, speech signal processing that converts the sound into electrical signals, a piezoelectric vibrator that converts the electrical signals into vibration signals, and so on.This paper mainly does with the part of speech signal processing in a new IMEDs. Firstly according to existing IMEDs, a new type of IMEDs has been designed and finite element model of middle ear has established. We got the middle ear transfer characteristics. Then using of frequency-division based on wavelet package and related theories about Bark spectrum, a set of signal processing algorithms has been designed. And a Simulink modal was established. Through the simulation, the correctness and feasibility of the algorithms was proofed. And then these algorithms were realized in DSP system. At last, the correctness and feasibility were demonstrated once again by an experiment. In this experiment the vibrator was drove to vibration.