(19)

(11)

EP 0 524 292 A1

(12)

(43) Date of publication: 27.01.1993 Bulletin 1993/04 (21) Application number: 92904538.0 (22) Date of filing: 13.02.1992

(51) International Patent Classification (IPC):  H03H 17/ 02( . ) (86) International application number: PCT/GB1992/000259 (87) International publication number: WO 1992/015151 (03.09.1992 Gazette 1992/23)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 13.02.1991 GB 19910002977 (71) Applicant: BRITISH BROADCASTING CORPORATION London W1A 1AA (GB)	(72) Inventor: DREWERY, John, Oliver Sutton Surrey SM2 5JS (GB) (74) Representative: Lloyd, Patrick Alexander Desmond  Reddie & Grose 16 Theobalds Road London WC1X 8PL London WC1X 8PL (GB)