Abstract: Methods and arrangements are described for developing a virtual channel matrix for mapping analysis channels to stimulation channels for a cochlear implant patient by selecting a stimulation channel and measuring the amplitude growth function for the selected stimulation channel in response to commands to the cochlear implant to apply electrical stimulation pulses for the stimulation channel, where each stimulation pulse comprises a negative and a positive phase separated in time by a first inter-phase-gap; and measuring the amplitude growth function for the selected stimulation channel in response to commands to the cochlear implant to apply electrical stimulation pulses for the stimulation channel, where each stimulation pulse comprises a negative and positive phase separated in time by a second inter-phase-gap and whereby the first and second inter-phase-gaps are different.

Abstract: A dual microphone signal processing arrangement for reducing reverberation is described. Time domain microphone signals are developed from a pair of sensing microphones. These are converted to the time-frequency domain to produce complex value spectra signals. A binary gain function applies frequency-specific energy ratios between the spectra signals to produce transformed spectra signals. A sigmoid gain function based on an inter-microphone coherence value between the transformed spectra signals is applied to the transformed spectra signals to produce coherence adapted spectra signals. And an inverse time-frequency transformation is applied to the coherence adjusted spectra signals to produce time-domain reverberation-compensated microphone signals with reduced reverberation components.

Abstract: A dual microphone signal processing arrangement for reducing reverberation is described. Time domain microphone signals are developed from a pair of sensing microphones. These are converted to the time-frequency domain to produce complex value spectra signals. A binary gain function applies frequency-specific energy ratios between the spectra signals to produce transformed spectra signals. A sigmoid gain function based on an inter-microphone coherence value between the transformed spectra signals is applied to the transformed spectra signals to produce coherence adapted spectra signals. And an inverse time-frequency transformation is applied to the coherence adjusted spectra signals to produce time-domain reverberation-compensated microphone signals with reduced reverberation components.

Abstract: A cochlear implant system is described which includes an electrode array for implantation in the scala tympani of a cochlea. Electrodes on the outer surface of the electrode array apply electrode stimulation signals to nearby neural tissue. An implantable stimulator module develops the electrode stimulation signals. The electrode stimulation signals have different waveforms. A basal waveform for one or more electrodes at the basal end of the electrode array has the form of a sequence of conventional high-amplitude short-duration electrode stimulation signals. An apical waveform for one or more electrodes at the apical end of the electrode array has the form of a sequence of lower-amplitude longer-duration electrode stimulation signals. The apical waveform is adapted to selectively stimulate peripheral neural processes towards the apical end of the electrode array so as to provide a tonotopic place-pitch response to the electrode stimulation signals.