Nonlinear Distortion in Modern Hearing Aids

1967 ◽  
Vol 10 (3) ◽  
pp. 586-592 ◽  
Author(s):  
Stephen H. Lotterman ◽  
Roger N. Kasten
Keyword(s):  
Hearing Aids ◽  
Nonlinear Distortion ◽  
Harmonic Distortion ◽  
Frequency Range ◽  
Distortion Products ◽  
Input Signals ◽  
Total Distortion

Nonlinear distortion was investigated in 367 new hearing aids. Among the first group of instruments examined, the level of harmonic distortion present at 500, 700, and 900 Hz was studied, together with the frequency and extent of maximum distortion. Ear-level instruments generally yielded lower distortion values than did body types. The frequency of maximum distortion tended to fall below 1000 Hz for body-worn instruments, while the frequencies at which maximum distortion occurred for the ear-level hearing aids were predominandy above 1000 Hz. The variability in total distortion exhibited within groups of fifteen instruments each of identical make and model was examined among a second group of instruments. Results for this procedure, which employed 60 dB SPL input signals and full-on acoustic gain settings, indicated that, although most of the instruments exhibited distortion products of less than 10% throughout their frequency range, total nonlinear distortion in excess of 20% was not uncommon among these hearing aids.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

scholarly journals The comparison of gains prescribed for digital behind-the-ear hearing aids using the manufacturer-specific and conventional prescriptive formulas

2021 ◽  
Author(s):  
Shahin Shyekhaghaei ◽  
Seyyed Jalal Sameni ◽  
Nariman Rahbar
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
Input Output ◽  
Frequency Range ◽  
Sensation Level ◽  
Input Intensity ◽  
Multi Stage ◽  
Significant Difference ◽  
Different Levels ◽  
Frequency Intensity

Background and Aim: There are several prescriptive formulas for covering a variety of hearing loss, each of which applies relatively different amplifications at different frequencies. This study aims to compare the gains prescribed for digital behind-the-ear (BTE) hearing aids by the Desired Sensation Level Multi-Stage [Input/Output] (DSLm[I/O]), National Acoustic Laboratories-non linear2 (NAL-NL2) and manufacturer-specific formulas at different levels of input intensity. Methods: The gain values in 12-channel BTE hearing aids prepared from four companies (Oticon, Phonak, ReSound and Siemens) were measured at three levels of input intensity (45, 65, and 85 dB SPL) and at a frequency range of 250−8000 Hz for two moderately severe flat and mild sloping to severe hearing losses by using the DSLm[I/O], NAL-NL2 and manufacturerspecific formulas in the Frye FP35 test box. Results: There was no significant difference between the four selected hearing aids in terms of prescribed gain values using the prescriptive formulas (p > 0.05). Conclusion: The DSLm[I/O] formula prescribes higher gain in the 12-channel BTE hearing aids from Oticon, Phonak and Siemens companies at all input intensities and frequencies for moderately severe flat and mild sloping to severe hearing losses compared to the NAL-NL2 formula and manufacturer-specific formulas (Voice Aligned Compression (VAC), Adaptive Phonak, Connexx Fit and audiogram+). Keywords: National acoustic laboratories-non linear2; desired sensation level multi-stage [input/output]; gain; frequency; intensity levels

Nonlinear distortion of signals radiated by vibroseis sources

Geophysics ◽  
2004 ◽  
Vol 69 (4) ◽  
pp. 968-977 ◽  
Author(s):  
Andrey V. Lebedev ◽  
Igor A. Beresnev
Keyword(s):  
Thin Layer ◽  
Nonlinear Response ◽  
Nonlinear Distortion ◽  
Near Field ◽  
Quantitative Description ◽  
Harmonic Distortion ◽  
Seismic Energy ◽  
Field Observations ◽  
Contact Nonlinearity ◽  
The Difference

A model of nonlinearity of the contact between the vibrator baseplate and the ground is proposed to describe the distortion of vibroseis signals in the near‐field. A thin layer between the baseplate and the soil exhibits a strong nonlinear response because of the difference in its rigidity between the compression and tension phases. The model allows for a quantitative description of the transmission of seismic energy into the ground, including the observed harmonic distortion. However, the contact nonlinearity does not lead to the dependence of wave traveltimes on the amplitude of the force applied to the ground. This fact can be used in field observations to localize the source of the observed harmonic distortion.

scholarly journals Cochlear Implantation Outcome in Children with DFNB1 locus Pathogenic Variants

2020 ◽  
Vol 9 (1) ◽  
pp. 228 ◽  
Author(s):  
Dominika Oziębło ◽  
Anita Obrycka ◽  
Artur Lorens ◽  
Henryk Skarżyński ◽  
Monika Ołdak
Keyword(s):  
Cochlear Implants ◽  
Hearing Aids ◽  
Cochlear Implantation ◽  
Treatment Method ◽  
Wide Frequency Range ◽  
Residual Hearing ◽  
Frequency Range ◽  
Pathogenic Variants ◽  
Auditory Development ◽  
Shed Light

Almost 60% of children with profound prelingual hearing loss (HL) have a genetic determinant of deafness, most frequently two DFNB1 locus (GJB2/GJB6 genes) recessive pathogenic variants. Only few studies combine HL etiology with cochlear implantation (CI) outcome. Patients with profound prelingual HL who received a cochlear implant before 24 months of age and had completed DFNB1 genetic testing were enrolled in the study (n = 196). LittlEARS questionnaire scores were used to assess auditory development. Our data show that children with DFNB1-related HL (n = 149) had good outcome from the CI (6.85, 22.24, and 28 scores at 0, 5, and 9 months post-CI, respectively). A better auditory development was achieved in patients who receive cochlear implants before 12 months of age. Children without residual hearing presented a higher rate of auditory development than children with responses in hearing aids over a wide frequency range prior to CI, but both groups reached a similar level of auditory development after 9 months post-CI. Our data shed light upon the benefits of CI in the homogenous group of patients with HL due to DFNB1 locus pathogenic variants and clearly demonstrate that very early CI is the most effective treatment method in this group of patients.

Compression in the Time Domain

1993 ◽  
Vol 2 (2) ◽  
pp. 41-46 ◽  
Author(s):  
Harry Teder
Keyword(s):  
Hearing Aids ◽  
Time Domain ◽  
Amplitude Envelope ◽  
High Input ◽  
Distortion Products ◽  
The Time Domain

High input levels can cause saturation and "fast pumping" effects in hearing aids. The resulting distortion products and changes in speech amplitude envelope are examined in the time domain. Spectrograms reveal changes in speech elements not apparent with time domain methods.

Performance of Individual Hearing Aids Utilizing Microphone and Induction Coil Input

1971 ◽  
Vol 14 (2) ◽  
pp. 365-371 ◽  
Author(s):  
Richard J. Sung ◽  
William R. Hodgson
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Harmonic Distortion ◽  
Physical Characteristics ◽  
Induction Coil ◽  
Body Type ◽  
High Frequency Response ◽  
Physical Measurements

Physical measurements of gain, maximum power output, frequency response, and harmonic distortion were made on each of two body-type hearing aids on both the microphone and induction coil settings. In addition, we investigated speech intelligibility through each aid, for both acoustic and magnetic input, using 32 normal-hearing subjects. Our findings indicated that different hearing aids provide different sensitivity for loop induction. For a given hearing aid, physical characteristics varied between the microphone and the telephone coil settings. The intelligibility of speech produced by a given mode of signal input, either microphone or telephone coil, was dependent on physical characteristics of the hearing aid. The usable high-frequency response and the configuration of the response curve in the region of 1500 to 3000 Hz appeared to be associated with the intelligibility of monosyllabic words.

Loudness Matching of Signals Spectrally Shaped by a Simulated Hearing Aid

1993 ◽  
Vol 36 (2) ◽  
pp. 357-364 ◽  
Author(s):  
Jerry Punch ◽  
Brad Rakerd
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
General Pattern ◽  
Preliminary Evidence ◽  
Multiple Frequency ◽  
Frequency Range ◽  
Frequency Responses ◽  
The Individual ◽  
Spectral Tilt

A hearing aid with multiple frequency responses was simulated by programming an equalizer to produce spectral tilt factors of -6, 0, and +6 dB/octave over the frequency range from 0.25 kHz to 4 kHz. Listeners with normal hearing matched the loudness of signals (speech and white noise) that were shaped by these different equalizer settings and delivered via an insert earphone. All signals with spectra that were tilted, either negatively or positively, were perceived as louder than untilted signals. The general pattern of loudness matching was similar across subjects, and intrasubject judgments were found to be highly transitive. A measure of signal power was found to account only moderately well for the individual data. Preliminary evidence from a follow-up study using tilt factors less severe than those used in the main experiment suggests that loudness differences are roughly proportional to the degree of spectral tilt. The incorporation of level corrections approximating those necessary to achieve equal loudness is recommended in the fitting of programmable hearing aids.

scholarly journals Impact of harmonic distortion on the supraharmonic emission of pulsewidth modulated single-phase power electronic devices

2021 ◽  
Vol 19 ◽  
pp. 577-582
Author(s):  
E. Kaufhold ◽  
◽  
J. Meyer ◽  
P. Schegner
Keyword(s):  
Single Phase ◽  
Electronic Devices ◽  
Harmonic Distortion ◽  
Power Electronic ◽  
Frequency Range ◽  
Pulse Width Modulated ◽  
Current State ◽  
Photovoltaic Applications ◽  
Frequency Coupling ◽  
Single Phase Inverter

This study demonstrates the frequency coupling in pulse width modulated (PWM) single-phase converters and inverters. As current state of the art, the harmonic frequency range, e.g. from fundamental frequency up to 2 kHz, is typically assessed separately from the so-called supraharmonic frequency range, i.e. above 2 kHz up to 150 kHz. The frequency coupling between the harmonic and supraharmonic frequency range has not been thoroughly studied and is currently often neglected in the design process as well as for the analysis of the emission of power electronic devices. The aim of this study is to analyse the behaviour of the frequency coupling between the harmonic and the supraharmonic range. In addition, laboratory measurements of a commercially available single-phase inverter for photovoltaic applications are shown to verify the findings.

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