Wearable Digital Speech Processor for Cochlear Implants Using a TMS320C25.

Based on a single-chip DSP (TMS320C25, Texas Instruments) a programmable battery-operated sound processor with a digital encoder interface for the Nucleus-22 cochlear implant (CI) was built. The number of quasi-simultaneously addressed electrodes is only limited by the selected pulse width and the maximum rate of stimulation and can be as high as 10 electrodes at 300 Hz repetition rate. Implementation of various processing strategies (formant or channel vocoder, filterbank, zero crossings, etc.