Feedback Cancellation With Probe Shaping Compensation

Adaptive feedback cancellation methods may integrate the use of probe signals to assist with the biased optimal solution in acoustic systems working in closed-loop. However, injecting a probe noise in the loudspeaker decreases the signal quality perceived by users of assistive listening devices. To...

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Bibliographic Details
Published in:IEEE signal processing letters 2014-03, Vol.21 (3), p.365-369
Main Authors: Nakagawa, C. Renato C., Nordholm, Sven, Wei-Yong Yan
Format: Article
Language:English
Subjects:
Acoustic feedback
Acoustics
Algorithms
bias problem
Cancellation
Channels
Compensation
Convergence
Correlation
Delay
Delays
Economic models
Feedback
feedback cancellation
hearing aids
Loudspeakers
Masking
Noise
probe injection
Probes
System performance
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Summary:Adaptive feedback cancellation methods may integrate the use of probe signals to assist with the biased optimal solution in acoustic systems working in closed-loop. However, injecting a probe noise in the loudspeaker decreases the signal quality perceived by users of assistive listening devices. To counter this, probe signals are usually shaped to provide some level of perceptual masking. In this letter we show the impact of using a shaping filter on the system behavior in terms of convergence rate and steady state error. From this study, it can be concluded that shaping the probe signal may have detrimental influence in terms of system performance. Accordingly, we propose to use the unshaped probe signal combined with an inverse filter of the shaping filter to identify the feedback channel. This restructure of the problem restores convergence rate of LMS type algorithms. Furthermore, we also show that an adequate forward path delay is required to obtain an unbiased solution and that the suggested scheme reduces this delay.
ISSN:1070-9908
1558-2361
DOI:10.1109/LSP.2014.2301832