Topic
Gain before feedback
About: Gain before feedback is a research topic. Over the lifetime, 249 publications have been published within this topic receiving 4873 citations.
Papers published on a yearly basis
Papers
TL;DR: Analysis of the steady-state convergence behavior of LMS-based adaptive algorithms when used in continuous adaptation to reduce acoustic feedback shows that by the use of a delay in the forward or cancellation paths of the hearing aid plant, it is possible to reduce this bias by more than 15 dB.
Abstract: Acoustic feedback is a problem in hearing aids that contain a substantial amount of gain, hearing aids that are used in conjunction with vented or open molds, and in-the-ear hearing aids. Acoustic feedback is both annoying and reduces the maximum usable gain of hearing-aid devices. This paper studies analytically the steady-state convergence behavior of LMS-based adaptive algorithms when used in continuous adaptation to reduce acoustic feedback. A bias is found in the adaptive filter's estimate of the hearing-aid acoustic feedback path. Methods for reducing this bias and producing an improved estimate of the acoustic feedback path are analyzed and compared. It is shown that by the use of a delay in the forward or cancellation paths of the hearing aid plant, and for representative feedback paths, it is possible to reduce this bias by more than 15 dB.
174 citations
Patent•
22 Jun 1993
TL;DR: In this paper, an audio frequency compressing system for amplifying an input signal to produce a power output signal while removing high-level signals which could harm a listener is described.
Abstract: An audio frequency compressing system for amplifying an input signal to produce a power output signal while removing high-level signals which could harm a listener. Gain control in the feedback path of an amplifier includes both a gain controller circuit for supplying a constant feedback impedance and a plurality of resistors which can be coupled to the gain controller circuit to increase or decrease the feedback impedance. Coupling of the resistors to the gain controller circuit is controlled by a feedback control circuit having both an automatic gain control circuit and a continuous high-level protection circuit.
154 citations
TL;DR: In this paper, an in-the-ear hearing aid with a shell and a face plate is presented, where the shell is molded to custom fit a hearing aid user's ear and a switch mechanism is included having an operator extending through the housing for switching the hearing aid between a non-directional mode and a directional mode.
Abstract: Apparatus for use as an in-the-ear hearing aid. The apparatus includes a housing having a shell and a face plate, wherein the shell is molded to custom fit a hearing aid user's ear. A first non-directional microphone system is included having a first output signal representative of the sound received. A second non-directional microphone system is included having a second output signal representative of the sound received. A switch mechanism is included having an operator extending through the housing for switching the in-the-ear hearing aid between a non-directional mode and a directional mode. In the directional mode, the microphone system is adjustable between a cardioid and super cardioid polar output pattern.
153 citations
TL;DR: In this article, a limiter is inserted in the main electrical pathway between the microphone and the receiver to provide stability in the presence of sudden sound bursts, and a noise signal is injected continuously into the electrical circuit and is used to adapt the characteristics of the filter to accommodate changes in the acoustic coupling.
Abstract: A hearing aid includes a filter in an electrical feedback path, the characteristics of which filter are calculated to model acoustic coupling between the receiver and microphone of the aid. A limiter is inserted in the main electrical pathway between the microphone and the receiver to provide stability in the presence of sudden sound bursts. A noise signal is injected continuously into the electrical circuit and is used to adapt the characteristics of the filter to accommodate changes in the acoustic coupling. The level of the noise signal can be varied to match changes in residual signal level to maintain signal to noise ratio and to optimize rate of adaption commensurate with satisfactory hearing function while the noise itself is unobtrusive to the user.
116 citations
TL;DR: In this article, a feedback cancellation system for a hearing aid or the like adapts a first filter in the feedback path that models the quickly varying portion of the hearing aid feedback path, and adapt a second filter that is used either as a reference filter for constrained adaptation or to model more slowly varying portions of the feedback process.
Abstract: A feedback cancellation system for a hearing aid or the like adapts a first filter in the feedback path that models the quickly varying portion of the hearing aid feedback path, and adapts a second filter in the feedback path that is used either as a reference filter for constrained adaptation or to model more slowly varying portions of the feedback path. The second filter is updated only when the hearing aid signals indicate that an accurate estimate of the feedback path can be obtained. Changes in the second filter are then monitored to detect changes in the hearing aid feedback path. The first filter is adaptively updated at least when the condition of the signal indicates that an accurate estimate of physical feedback cannot be made. It may be updated on a continuous or frequent basis.
107 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2018 | 1 |
| 2017 | 3 |
| 2016 | 6 |
| 2015 | 9 |
| 2014 | 14 |
| 2013 | 15 |