Projects per year
Abstract
In this dissertation, the feedback whistling problem with digital hearing instruments
is investigated. The work focuses on the properties of the feedback
path, the modelling of the feedback path and the feedback suppression techniques.
The properties and modelling of the feedback path are first discussed. Along
the propagation path, different components compose the feedback path. The
effects of these components are analyzed and categorized. Accordingly an
ideal feedback path model, which consists of a fixed model, a slowing varying
model and a fast varying model, is suggested in the dissertation. Methods
to extract the fixed model are proposed and proved to be effective in representing
the invariant part of the feedback path. Based on the investigation
of the dynamic changes of the feedback path in adverse situations, for example
when the user picks up the telephone handset, a reflection model is
developed as one type of the fast varying models.
The techniques to suppress the feedback are then reviewed. To improve the
existing feedback suppression systems, two approaches are proposed to address
the so-called “bias problem”. The first approach improves the performance
of the adaptive feedback canceller with filtered-X adaptation by injecting
nearly inaudible noise. The second approach uses a linear predicative
coding based vocoder to synthesize the hearing-aid output in order to decorrelate
the hearing-aid output signal and the desired input signal.
In the end, a discussion about the use of the proposed feedback path models
in the feedback cancellation systems is presented.
Original language | English |
---|
Place of Publication | Kgs. Lyngby, Denmark |
---|---|
Publisher | Technical University of Denmark |
Number of pages | 117 |
ISBN (Print) | 978-87-92465-26-9 |
Publication status | Published - Apr 2010 |
Fingerprint
Dive into the research topics of 'Feedback suppression in digital hearing instruments'. Together they form a unique fingerprint.Projects
- 1 Finished
-
New Strategies for Feedback Suppression in Hearing Instruments
Guilin, M. (PhD Student), Jacobsen, F. (Main Supervisor), Agerkvist, F. T. (Supervisor), Gran, F. (Supervisor), Buchholz, J. (Examiner), Kates, J. M. (Examiner) & Rubak, P. (Examiner)
01/05/2007 → 01/09/2010
Project: PhD