Nonlinear processing with Mth-order signals

2006 ◽  
pp. 119-129 ◽  
Author(s):  
F. J. Bugnon ◽  
R. R. Mohler
Keyword(s):  
Nonlinear Processing

scholarly journals Mechanisms of Spectrotemporal Modulation Detection for Normal- and Hearing-Impaired Listeners

2021 ◽  
Vol 25 ◽  
pp. 233121652097802
Author(s):  
Emmanuel Ponsot ◽  
Léo Varnet ◽  
Nicolas Wallaert ◽  
Elza Daoud ◽  
Shihab A. Shamma ◽  
...  
Keyword(s):  
Speech Intelligibility ◽  
Hearing Impaired ◽  
Temporal Modulation ◽  
Computational Tools ◽  
Cochlear Tuning ◽  
Cochlear Hearing Loss ◽  
Nonlinear Processing ◽  
Linear Band ◽  
Band Pass ◽  
Modulation Filter

Spectrotemporal modulations (STM) are essential features of speech signals that make them intelligible. While their encoding has been widely investigated in neurophysiology, we still lack a full understanding of how STMs are processed at the behavioral level and how cochlear hearing loss impacts this processing. Here, we introduce a novel methodological framework based on psychophysical reverse correlation deployed in the modulation space to characterize the mechanisms underlying STM detection in noise. We derive perceptual filters for young normal-hearing and older hearing-impaired individuals performing a detection task of an elementary target STM (a given product of temporal and spectral modulations) embedded in other masking STMs. Analyzed with computational tools, our data show that both groups rely on a comparable linear (band-pass)–nonlinear processing cascade, which can be well accounted for by a temporal modulation filter bank model combined with cross-correlation against the target representation. Our results also suggest that the modulation mistuning observed for the hearing-impaired group results primarily from broader cochlear filters. Yet, we find idiosyncratic behaviors that cannot be captured by cochlear tuning alone, highlighting the need to consider variability originating from additional mechanisms. Overall, this integrated experimental-computational approach offers a principled way to assess suprathreshold processing distortions in each individual and could thus be used to further investigate interindividual differences in speech intelligibility.

Nonlinear processing for enhanced delay-Doppler resolution of multiple targets based on an improved radar waveform

2017 ◽  
Vol 130 ◽  
pp. 355-364 ◽  
Author(s):  
Jiahua Zhu ◽  
Yongping Song ◽  
Chongyi Fan ◽  
Xiaotao Huang
Keyword(s):  
Multiple Targets ◽  
Nonlinear Processing

Nonlinear Processing

DAFX ◽  
2004 ◽  
pp. 93-136
Author(s):  
P. Dutilleux ◽  
U. Zölzer
Keyword(s):  
Nonlinear Processing

Auditory Distortion Products Measured With Averaged Auditory Evoked Potentials

1992 ◽  
Vol 35 (1) ◽  
pp. 157-166 ◽  
Author(s):  
Mark E. Chertoff ◽  
Kurt E. Hecox ◽  
Robert Goldstein
Keyword(s):  
High Frequency ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Low Frequency ◽  
Auditory Evoked Potential ◽  
Noise Floor ◽  
Distortion Products ◽  
Nonlinear Processing ◽  
Cochlear Damage ◽  
Primary Frequency

The purpose of this investigation was to describe the properties of averaged auditory evoked potential distortion products (AEP-DPs) in guinea pigs. This study provided a step toward developing a clinical index of nonlinear processing of auditory signals and supplied a baseline for studies evaluating the effect of cochlear damage on AEP-DPs. The amplitude of the AEP-DPs was evaluated as a function of f2/fl ratio (1.12–1.52) and primary frequency (500 Hz–2000 Hz). The amplitude of the AEP cubic difference tone (AEP-CDT) increased with increasing f2/fl ratio for the 500-Hz f1 primary and remained constant for the 800-Hz and 1700-Hz f1 primaries. The AEP-CDT generated by the 1100-Hz and 1400 Hz f1 primaries was maximum for the middle f2/fl ratios (1.22, 1.32, and 1.42). The AEP-CDT could not be distinguished from the noise floor for the 2000-Hz f1 primary. The AEP difference tone (AEP-DT) was larger and more frequently identified than the AEP-CDT. The amplitude of the AEP-DT decreased with an increase in f2/f1 ratio. The decrease was more pronounced for low-frequency f1 primaries than for high-frequency f1 primaries.

scholarly journals Contrast Sensitivity Is Enhanced by Expansive Nonlinear Processing in the Lateral Geniculate Nucleus

2008 ◽  
Vol 99 (1) ◽  
pp. 367-372 ◽  
Author(s):  
Thang Duong ◽  
Ralph D. Freeman
Keyword(s):  
Visual Cortex ◽  
Lateral Geniculate Nucleus ◽  
Visual Processing ◽  
Linear Prediction ◽  
Visual Pathway ◽  
Low Contrast ◽  
Response Data ◽  
Lateral Geniculate ◽  
Nonlinear Processing ◽  
Contrast Response

The firing rates of neurons in the central visual pathway vary with stimulus strength, but not necessarily in a linear manner. In the contrast domain, the neural response function for cells in the primary visual cortex is characterized by expansive and compressive nonlinearities at low and high contrasts, respectively. A compressive nonlinearity at high contrast is also found for early visual pathway neurons in the lateral geniculate nucleus (LGN). This mechanism affects processing in the visual cortex. A fundamentally related issue is the possibility of an expansive nonlinearity at low contrast in LGN. To examine this possibility, we have obtained contrast–response data for a population of LGN neurons. We find for most cells that the best-fit function requires an expansive component. Additionally, we have measured the responses of LGN neurons to m-sequence white noise and examined the static relationship between a linear prediction and actual spike rate. We find that this static relationship is well fit by an expansive nonlinear power law with average exponent of 1.58. These results demonstrate that neurons in early visual pathways exhibit expansive nonlinear responses at low contrasts. Although this thalamic expansive nonlinearity has been largely ignored in models of early visual processing, it may have important consequences because it potentially affects the interpretation of a variety of visual functions.

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