(19)

(11)

EP 0 452 370 A1

(12)

(43) Date of publication: 23.10.1991 Bulletin 1991/43 (21) Application number: 90901498.0 (22) Date of filing: 29.12.1989

(51) International Patent Classification (IPC):  F16F 15/ 02( . ) G10K 11/ 16( . ) H04R 1/ 02( . ) F16F 7/ 108( . ) G10K 11/ 172( . ) (86) International application number: PCT/US1989/005862 (87) International publication number: WO 1990/007673 (12.07.1990 Gazette 1990/16)

(84) Designated Contracting States: AT BE CH DE ES FR GB IT LI LU NL SE (30) Priority: 30.12.1988 US 19880292412 (71) Applicant: DELTA TECH RESEARCH Mountain View, CA 94039 (US)	(72) Inventor: THOMASEN, Leonard, N. Sunnyvale, CA 94086 (US) (74) Representative: Waxweiler, Jean  Dennemeyer & Associates Sàrl P.O. Box 1502 L-1015 Luxembourg L-1015 Luxembourg (LU)