The Design Of Electronic Cochlea Audio Signal Processing System

The Electronic Cochlea is a kind of medical device,which uses microelectronics technology to stimulate the auditory nerve with a limited number of electrodes to restore the hearing of the deaf,its basic principle is to imitate the human auditory mechanism of peripheral nerve,with weak current pulse to directly stimulate and excite auditory nerve in the cochlea of the deaf,to reproduce the cochlear auditory sensory mechanism.As a key components in Electronic Cochlea,the speech signal processing circuit's function is to convert speech signals into electrical signals which is used to stimulate the person ear auditory nerves.Since the research of Electronic Cochlea started late in our country,the Electronic Cochlea's key technologies including the design of speech signals processing circuit are needed to be further improved.The design of Electronic cochlea audio signal processing circuit in this project is helpful to improve the Electronic Cochlea's progress in our country,which will benefit more than 20 million profoundly deaf patients,and will bring tremendous social and economic benefits.Based on the analysis of the physiological structure of human hearing organ,the Electronic Cochlea audio signal processing algorithm and related key technologies,a Electronic Cochlea audio signal processing system had been designed in this project.The circuit uses the fixed-point digital signal processor chip(DSP)TMS320C5515 to construct the speech signal processing module,designed the speech signal acquisition and coding circuit by the audio codec chip TLV320AIC3204 and designed the system control circuit by STM32F103,RF coil was used to construct the signal transmitting module and designed the other peripheral circuits,the digital signal processing part is the core module.Based on the analysis of speech signal processing scheme feature extraction and filter group,this paper adopts the spectral maxima sound processor(SMSP),which is a speech algorithm not only ensured the envelope of the speech signal,but also reduced the power consumption of the RF emission.Finally,the corresponding speech signal processing strategy had been actualized in the DSP's development environment---code composer studio software.DSP sends the processed speech signals to MCU,and MCU processes the speech signals according to the RF protocol and convents the speech signals into the signals that could provide the speech information for the stimulator.Based on the design of speech signal acquisition,processing and transmitting,the entire layout of the PCB design optimization had been carried on.At the same time,according to the performance index of each module,design the related test plan,analyze the data and finally carry out clinical trial.The results show that the system meets the design requirements,and each module has the correct function,and has the clinical experimental conditions.According to the first clinical experimental phenomenon,the system software is further optimized,again in clinical experiment,for the first time,the patient can hear about 30%?40%,through repeated training can hear about 60%?70%,and the patients reflect the system noise can acceptable.The design of electronic cochlea audio signal processing circuit in this project can reproduce the cochlear auditory sensory mechanism,and the clinical effect is better.This project is helpful to improve the level of Electronic Cochlea's progress in our country,and can improve the hearing disabled people's lives and work.