SPEECH PROCESSORS

摘要

This specification discloses signal processing systems for converting a speech signal into a data signal for controlling a hearing prosthesis. The prosthesis includes an implanted electrode array which is adapted to stimulate auditory nerve fibres of the patient. Stimulation occurs by application of electrical currents to selected electrodes in the array. The processing system generates an input signal corresponding to a received speech signal and a processing system estimates the amplitude and frequency of the fundamental voicing component of the speech signal and also estimates the amplitude and frequency of at least one formant of the speech signal. The system includes programmable means for producing instruction data which causes application of electrical currents to selected groups of electrodes in the array to stimulate nerve fibers. The system includes use of programmable data which defines a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency and data defining a predetermined relationship between another formant frequency and the delay between stimulation of each electrode in each of the groups based on psychophysical testing of the patient. The system provides selection of the electrodes based on the estimated frequency of the formant so as to produce the desired percepts in the patient. The programmable means within the system is further programmable to produce data which determines the level of stimulation of each selected group of electrodes and determines the delay between stimulation of electrodes in each group dependent upon an estimated amplitude of the formants of the speech signal as well as on predetermined data relating to the sensitivity of each electrode implanted in the patient.