Patent ID: 7627379

Claim:
A method of sound conversion in a cochlear implant in which an electrode array of a plurality of electrodes is arranged within a cochlea, each of the electrodes corresponding to one of a plurality channels, electrical stimulation pulses are generated by transmitting sound information sampled via a microphone to the electrodes, and the acoustic sense of the user is reinforced by transmitting the sound information to the cochlea as electrical stimulation pulses, the method comprises steps of: (1) discriminating the sound information into respective frequency bands using a plurality of band pass filters within a signal frame of a predetermined sampling period, to generate a sound information comprising a combination of channel information, time information and signal level information which is represented as an amplitude-time matrix(ATM), then; (2) successively repeating the following steps identified as (a) to (d); (a) adding to the sound information of ATM an information indicative of which channel corresponds to each frequency band; (b) determining a maximum value that is the highest signal level of each sound information of ATM, based on a magnitude of signal level of each sound information; (c) adjusting the number of the stimulation pulses to a frequency allowed in each channel in relation to said maximum value by leaving, within a time interval within each channel, only a sound information having the highest signal level in each channel, so that the other sound information within the time interval within each respective channel is abandoned; then (d) adjusting the number of the stimulation pulses to a frequency allowed in all channels by leaving, for a given time interval for all channels, only a sound information having the highest signal level of the sound information left in said all channels, so that the other sound information in said all channels is abandoned; and generating the stimulation pulses by providing the remaining sound information having the combination of ATM to the electrodes corresponding to the respective channels.