| Popis: |
Two new processing strategies have been implemented on a cochlear implant digital speech processor (CIDSP) for the Nucleus 22‐electrode cochlear prosthesis using a single chip digital signal processor (TMS320C25, Texas Instruments). The first approach, pitch excited sampler (PES), is based on the classical channel vocoder concept whereby the spectral energy of a number of logarithmically spaced frequency bands is transformed into appropriate electrical stimulation parameters for up to 22 electrodes using a voice pitch synchronous pulse rate at any electrode. The second approach, continuous interleaved sampler (CIS), uses a maximally high pitch‐independent stimulation pulse rate on a selected number of electrodes. Optimization and fine‐tuning of processing parameters for these coding strategies is based on a number of psychophysical experiments and some additional constraints. Evaluation experiments with seven cochlear implant users resulted in significantly improved performance in consonant identification... |
