Predicting the Intelligibility of Cochlear-implant Vocoded
Speech from Objective Quality Measure(5)
Department of Electrical Engineering, The University of Texas at Dallas, Richardson, Texas75083, USA
Chairman:Hung-Chi Yang
Presenter: Yu-Kai Wang
Advisor: Dr. Yeou-Jiunn Chen
Date: 2012.12.12
Material and Methods
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2.3 Signal processing
The stimuli were presented in two signal processing
conditions.
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Tone-vocoder.
EAS-vocoder.
The first processing condition (tone-vocoder) .
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To simulate eight-channel electrical stimulation.
Eightd-channel sinewave-excited vocoder.
Through a pre -emphasis filter (2000-Hz cutoff) with 3 dB/octave
roll-off.
Band-passed into eight frequency bands btween 80 and 6000 Hz.
Sixth-order Butterworth filter.
Material and Methods
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The envelope of the signal was extracted by.
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Full-wave rectification
Low –pass filtering using a second-order Butterworth filter (400Hz cutoff).
Sinusoids were generated with amplitudes equal to the rootmean-square of the envelopes (computed every 4 ms) .
Frequencies equal to the center frequencies of the bandpass
filters.