Abstract: A method and apparatus for detecting an envelope of an audio signal, and a method and apparatus for enhancing the pitch cue of an audio signal perceived by a cochlear implant patient where the audio signal is processed and input to an implant device of the recipient. The methods and apparatuses use techniques such as filtering, rectifying, detecting peak values, sampling, resetting, comparing and multiplying various signals to detect the envelope or enhance the pitch cue of the audio signal.

Abstract: In one embodiment, an apparatus for processing sound includes a means (401) for analyzing a sound signal into a number of frequency bands and a means (403) for applying variable gain to each frequency band independently. Gain in applied under control of a number of gain comparator means (409) each of which generates a number of statistical distribution estimates in respect of each signal and compares those estimates to predetermined hearing response parameters stored in memory (411). The numerous gain compensated frequency bands are then combined (415) in order to generate a single sound signal. The apparatus may be implemented in dedicated hardware embodiment or by software running on a microprocessor.

Abstract: An improved sound processor, with particular application to stimulation of implanted electrode arrays, such as cochlear implants. The processor channelizes received sound signals into at least ten analysis channels to produce amplitude signals for each channel. A predefined number of channels with the largest amplitude are used to modulate stimuli for the implanted array. The predefined number is at least four, and less than or equal to half the number of analysis channels.

Abstract: A device for controlling stimulating currents in prosthetic devices in which a series of short spaced current pulses are delivered to electrodes with intervals between the pulses of zero current having a duration longer than that of each spaced pulse, the waveform of the stimulus current comprising a series of said spaced pulses of one polarity followed by an equal number of said spaced pulses of opposite polarity whereby the sum of all of the electrical charge transferred through each electrode is approximately zero at the end of a stimulating current waveform. In a hearing prosthesis in which bipolar pairs of electrodes are used to stimulate hearing nerves, the spaced pulses are delivered cyclically to the bipolar pairs of electrodes whereby the spaced pulses are delivered to one electrode pair during the zero current periods of the spaced pulses delivered to another electrode pair whereby the electrical stimulation caused by said electrodes is substantially simultaneous.