The Research Of A Speech Processor In Cochlear Implant

The sense of hearing is the way people obtain external information, and exchange with the external world. But there exists a large crowd of people with obstacle of sense of hearing. Most deep deaf patients lose the ability of changing the voice into the electric signal, and conveying to the brain through the neural fibre of sense of hearing. The cochlear implant is a device to cure nerve deaf. Its basic principle is to replace the function of hair cells to finish transfer from sound to electricity, and stimulate the auditory nerve directly with the proper current pulse through the speech processor, thus making the patient recapture the sense of hearing. There are patients in various degree of hearing lost in our country, most of whom are deaf. Audiphones have nothing to do with the deaf patients, the cochlear implant can help the patients resume hearing on a large scale, To develop cochlear implant independently, is helpful to the undertaking to deaf patients, bringing enormous social and economic benefits.A cochlear implant system mainly include speech processor and planted electrode. The function of the speech processor lies in dealing with speech signal and producing the pulse which electrodes need to stimulate cochlea. The purpose of this subject is set up the basic system structure of the cochlear implant's speech processor, make the speech processor can finish the function of signal processing on the hardware and software, and offer some suggestions on the circuit design of domestic cochlear implant's speech processor.In this subject, the speech processor adopts the systematic structure of the digital signal processor TMS320VC5409, and finished the design of other hardwares according to the characteristic of DSP. The speech procesor adopts the scheme of the signal compress analog(CA) and cooperates with the treatment based on the speech feature-extraction strategics. Because it is difficult to produce electrode at home, the speech processor is still unable to go on some animal test. The auther has carried on the artificial test of the signal of speech by using MATLAB6.5 and two channel color digital phosphor oscilloscope TDS3052B. The result of the test shows the treated speech signal and primitive signal are similar in spectrum, this indicates the treated speech signal includes the information of the original signal. So we can claim the patient can resume certain sense of hearing after wearing a speech processor.Reviewing the research of this subject, the designed speech processor has the...