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EURASIP Journal on Audio, Speech, and Music Processing
Figure 18 | EURASIP Journal on Audio, Speech, and Music Processing

Figure 18

From: Pitch Ranking, Melody Contour and Instrument Recognition Tests Using Two Semitone Frequency Maps for Nucleus Cochlear Implants

Figure 18

Power spectrum estimates for both the G4# reference (black) and D5 probe (6-semitone interval) (gray) signals for the unprocessed tones (a) and using Smt-MF mapping after AMO processing (b). The fundamental frequency of the reference tone (414 Hz) is filtered out because it is below 440 Hz (shaded area in (a)), while that of the probe (585 Hz) is retained. After Smt-MF processing with the AMO, comparisons of the unfiltered first overtone's peak above the theoretical noise floor of the power spectral density (−48.2 dB) which is double the theoretical noise floor of FFT in dB [28] (shaded area in (b)) in the reference (1070 Hz) with the fundamental of the probe (~859 Hz) would then result in a pitch reversal.

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