DVE system with instability detection

Details DVE system with instability detection DVE system with instability detection

2001-02-21

2003-12-16

Isen, Forester W. (Department: 2644)

Electrical audio signal processing systems and devices

Feedback suppression

C381S083000

Reexamination Certificate

active

06665411

ABSTRACT:

BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to digital voice enhancement, DVE, communication systems, and more particularly to feedback instability detection and corrective action.
The invention may be used in duplex systems, for example as shown in U.S. Pat. No. 5,033,082, and U.S. application Ser. No. 08/927,874, filed Sep. 11, 1997, simplex systems, for example as shown in U.S. application Ser. No. 09/050,511, filed Mar. 30, 1998, all incorporated herein by reference, and in other systems.
The DVE communication system includes a first acoustic zone, a second acoustic zone, a microphone at the first zone, and a loudspeaker at the second zone and electrically coupled to the microphone such that the speech of a person at the first zone can be heard by a person at the second zone as transmitted by an electrical signal from the microphone to the loudspeaker.
Under adverse conditions, instabilities can inadvertently cause feedback in DVE systems. This feedback causes the DVE controller outputs to diverge unbounded at the frequency of instability. The end result is a loud objectionable tonal squeal or screech that grows in magnitude. This is an abnormal operational state of the DVE system which must be detected and suppressed.
The present invention uses signal statistics of the electrical signal transmitted to the loudspeaker to detect a condition of instability. An instability detector detects an unstable acoustic feedback condition from the loudspeaker to the microphone by sensing a condition of the electrical signal transmitted from the microphone to the loudspeaker, and a corrective processor responds to the instability detector to modify the noted electrical signal to reduce unstable acoustic feedback.


REFERENCES:
patent: 4677676 (1987-06-01), Eriksson
patent: 4677677 (1987-06-01), Eriksson
patent: 4987598 (1991-01-01), Eriksson
patent: 5033082 (1991-07-01), Eriksson et al.
patent: 5172416 (1992-12-01), Allie et al.
patent: 5206911 (1993-04-01), Eriksson et al.
patent: 5323459 (1994-06-01), Hirano
patent: 5377277 (1994-12-01), Bisping
patent: 5386477 (1995-01-01), Popovich et al.
patent: 5396561 (1995-03-01), Popovich et al.
patent: 5442712 (1995-08-01), Kawamura et al.
patent: 5473686 (1995-12-01), Virdee
patent: 5621803 (1997-04-01), Laak
patent: 5677987 (1997-10-01), Seki et al.
patent: 5680337 (1997-10-01), Pedersen et al.
patent: 5706344 (1998-01-01), Finn
patent: 5710822 (1998-01-01), Steenhagen et al.
patent: 5715320 (1998-02-01), Allie et al.
patent: 5910994 (1999-06-01), Lane et al.
patent: 6252969 (2001-06-01), Ando
patent: 6295364 (2001-09-01), Finn et al.
Digital Processing of Speech Signals, Lawrence R. Rabiner, Ronald W. Schafer, 1978, Bell Laboratories, Inc. Prentice-Hall, pp. 120-126.
Handbook For Digital Signal Processing, Sanjit K. Mitra and James F. Kaiser, 1993, John Wiley & Sons, pp. 1193-1195.

Affiliated with

Also associated with

Rating

DVE system with instability detection does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with DVE system with instability detection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DVE system with instability detection will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3106658