Durations required to distinguish noise and tone: Effects of noise bandwidth and frequency.

Perceptual audio coders exploit the masking properties of the human auditory system to reduce the bit rate in audio recording and transmission systems; it is intended that the quantization noise is just masked by the audio signal. The effectiveness of the audio signal as a masker depends on whether it is tone-like or noise-like. The determination of this, both physically and perceptually, depends on the duration of the stimuli.

Masked threshold for noise bands masked by narrower bands of noise: Effects of masker bandwidth and center frequency.

This paper examines how masked thresholds depend on the masker bandwidth and center frequency when the masker has a smaller bandwidth than the signal. The signal bandwidth was equal to the equivalent rectangular bandwidth of the auditory filter and the masker bandwidth was 0.1, 0.

Current steering and results from novel speech coding strategies.

Objective: Advanced Bionics' cochlear implants have independent current sources that can share stimulation current between 2 contacts (Current Steering). By stimulating 2 adjacent electrodes with different weights, different pitches can be evoked, allowing to increase the number of processing channels.

Study Design: A counterbalanced crossover design was used to compare 3 different current steering implementations to the clinical HiRes strategy.

Results from a psychoacoustic model-based strategy for the nucleus-24 and freedom cochlear implants.

Objective: In normal-hearing listeners acoustic masking occurs depending on frequency, amplitude, and energy of specific signals. If the selection of stimulated channels in cochlear implant systems was based on psychoacoustic masking models, the bandwidth of the electrode/nerve interface could be used more effectively by concentrating on relevant signal components and neglecting those that are usually not perceived by normal hearing listeners. Subsequently, a new strategy called PACE (Psychoacoustic Advanced Combination Encoder) has been developed which uses a psychoacoustic model for the channel selection instead of the simple maxima selection algorithm of the ACE strategy.

An auditory model based strategy for cochlear implants.

A physiological and computational model of the human auditory system has been fitted in a signal processing strategy for cochlear implants (CIs). The aim of the new strategy is to obtain more natural sound in CIs by better mimicking the human auditory system. The new strategy was built in three independent stages as proposed in [6].