A new source‐filter model audio bandwidth extension using high frequency perception feature for IoT communications

2018 ◽  
Vol 32 (13) ◽  
Author(s):  
Lin Jiang ◽  
Shaoqian Yu ◽  
Xiaochen Wang ◽  
Chao Wang ◽  
Tonghan Wang
Keyword(s):  
High Frequency ◽  
Bandwidth Extension ◽  
Filter Model ◽  
Audio Bandwidth Extension

Nonlinear prediction with deep recurrent neural networks for non-blind audio bandwidth extension

2018 ◽  
Vol 15 (1) ◽  
pp. 72-85 ◽  
Author(s):  
Lin Jiang ◽  
Ruimin Hu ◽  
Xiaochen Wang ◽  
Weiping Tu ◽  
Maosheng Zhang
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Nonlinear Prediction ◽  
Bandwidth Extension ◽  
Audio Bandwidth Extension

scholarly journals Tutorial: Spectral bandwidth extension — Invention versus harmonic extrapolation

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. W1-W16 ◽  
Author(s):  
Chen Liang ◽  
John Castagna ◽  
Ricardo Zavala Torres
Keyword(s):  
Seismic Data ◽  
High Frequency ◽  
Low Frequency ◽  
Original Data ◽  
Spectral Bandwidth ◽  
Bandwidth Extension ◽  
Seismic Resolution ◽  
Earth Structures ◽  
Seismic Sections ◽  
Phase Acceleration

Various postprocessing methods can be applied to seismic data to extend the spectral bandwidth and potentially increase the seismic resolution. Frequency invention techniques, including phase acceleration and loop reconvolution, produce spectrally broadened seismic sections but arbitrarily create high frequencies without a physical basis. Tests in extending the bandwidth of low-frequency synthetics using these methods indicate that the invented frequencies do not tie high-frequency synthetics generated from the same reflectivity series. Furthermore, synthetic wedge models indicate that the invented high-frequency seismic traces do not improve thin-layer resolution. Frequency invention outputs may serve as useful attributes, but they should not be used for quantitative work and do not improve actual resolution. On the other hand, under appropriate circumstances, layer frequency responses can be extrapolated to frequencies outside the band of the original data using spectral periodicities determined from within the original seismic bandwidth. This can be accomplished by harmonic extrapolation. For blocky earth structures, synthetic tests show that such spectral extrapolation can readily double the bandwidth, even in the presence of noise. Wedge models illustrate the resulting resolution improvement. Synthetic tests suggest that the more complicated the earth structure, the less valid the bandwidth extension that harmonic extrapolation can achieve. Tests of the frequency invention methods and harmonic extrapolation on field seismic data demonstrate that (1) the frequency invention methods modify the original seismic band such that the original data cannot be recovered by simple band-pass filtering, whereas harmonic extrapolation can be filtered back to the original band with good fidelity and (2) harmonic extrapolation exhibits acceptable ties between real and synthetic seismic data outside the original seismic band, whereas frequency invention methods have unfavorable well ties in the cases studied.

Modulation Detection by Patients with Eighth-Nerve Tumors

1986 ◽  
Vol 29 (3) ◽  
pp. 413-419 ◽  
Author(s):  
C. Formby
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Modulation Frequency ◽  
Broad Band ◽  
Cutoff Frequency ◽  
Threshold Function ◽  
Filter Model ◽  
Eighth Nerve ◽  
Nerve Tumor ◽  
Method Of Adjustment

Detection thresholds for sinusoidally amplitude-modulated broad-band noise were measured as a function of modulation frequency for 4 normally hearing listeners and for 6 patients suffering eighth-nerve tumors. Measurements were obtained using a method-of-adjustment (MOA) procedure. On average, the threshold values revealed that more modulation was needed across all modulation frequencies for the patients' affected ears relative to either the normally hearing listeners or the patients' better ears. The cutoff frequency derived from the average modulation-threshold function (MTF) for the affected ears was about half the normal value. For a simple lowpass-filter model of the process, the latter result suggested a doubling of the auditory time constant in the affected ears. These patients, on average, exhibited the characteristic high-frequency audiometric hearing loss most often associated with eighth-nerve tumors. Their MTFs closely resembled MTFs described previously for high-frequency and simulated high-frequency audiometric hearing loss. The results of statistical analyses suggested that high-frequency audiometric hearing loss, irrespective of other influences, is the most parsimonious explanation for the increased modulation thresholds measured for the eighth-nerve tumor patients.

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