Volume 33 #3

Contents

1. The algorithm for simulation of dichromatic vision and its application for detecting color vision deficiencies
2. Discrimination of frequency-amplitude patterns of rippled-spectrum signals with spectraland temporal-processing mechanisms of frequency analysis
3. Involvement of protein kinase C in receptor-mediated signaling processes
4. Spectral model of a single-channel X-ray measuring instruments with polychromatic radiation
5. Safe speed control of unmanned ground vehicle under ego-position uncertainty
6. Recognition of projectively transformed planar figures. XIII. New methods for projectively-invariant description of ovals, using a T-polar curve

In normal-hearing listeners, thresholds of spectral ripple depth were measured as a function of ripple density. The test signal had a rippled spectrum with ripple phase reversals very 400 ms. The reference signal has either a rippled spectrum with constant ripple phase or had a flat (non-rippled) spectrum. Each measurement trial included one test and two reference signals, randomly alternated. The goal of the listener was to identify the test signal that differed from the two other (reference) signals. With a rippled-spectrum reference signal, the threshold of spectral ripple depth was 0.11 (dimensionless units) at low ripple densities of 2–3 ripples/oct; the threshold increased with increasing the ripple density and reached the maximum possible value of 1.0 at a density of 8.9 ripples/oct. With a flat-spectrum reference signal, thresholds were nearly the same as for the rippled-spectrum reference signals at ripple densities up to 7 ripples/oct; however, for the flat-spectrum reference signals, threshold rise got slower at higher ripple densities, and trached the maximum possible value of 1.0 at a density of 26 ripples/oct. It is suggested that the difference between results obtained with different reference signals originated from different contributions of the spectral and temporal mechanisms of frequency analysis. At lower ripple densities, discrimination both between two rippled spectra and between rippled and flat spectra proceeds mostly basing on the spectral-processing frequency- discrimination mechanism, whereas at higher ripple densities discrimination between rippled and flat spectra involves the temporal-processing mechanism.

Key words: hearing, rippled spectrum, resolution

DOI: 10.1134/S0235009219030065

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