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(11)

EP 0 615 648 A1

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(43) Date of publication: 21.09.1994 Bulletin 1994/38 (21) Application number: 92905531.0 (22) Date of filing: 02.12.1991

(51) International Patent Classification (IPC):  G10K 11/ 16( . ) G10K 11/ 178( . ) (86) International application number: PCT/US1991/008772 (87) International publication number: WO 1993/011529 (10.06.1993 Gazette 1993/14)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU MC NL SE (71) Applicant: NOISE CANCELLATION TECHNOLOGIES, INC. Linthicum, MD 21090 (US)	(72) Inventors: MC LOUGHLIN, Michael, P. Sykesville, MD 21784 (US) EGHTESADI, Khoscrow Shelton, CT 06484 (US) SMITH, Dexter Columbia, MD 21046 (US) ZIEGLER, Eldon, W., Jr. Columbia, MD 21046 (US) (74) Representative: Dauster, Hanjörg, Dipl.-Ing., et al  WILHELM & DAUSTER Patentanwälte Hospitalstrasse 8 D-70174 Stuttgart D-70174 Stuttgart (DE)