(19)

(11)

EP 0 948 875 A1

(12)

(43) Date of publication: 13.10.1999 Bulletin 1999/41 (21) Application number: 97950301.0 (22) Date of filing: 22.12.1997

(51) International Patent Classification (IPC):  H04R 3/ 00( . ) H04S 3/ 00( . ) (86) International application number: PCT/GB1997/003514 (87) International publication number: WO 1998/030064 (09.07.1998 Gazette 1998/27)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 28.12.1996 GB 19960027015 (71) Applicant: CENTRAL RESEARCH LABORATORIES LIMITED Hayes, Middlesex, UB3 1HH (GB)	(72) Inventor: NACKVI, Fawad Middlesex UB2 5PR (GB) (74) Representative: Leaman, Keith, et al  QED I.P. Services Limited, Dawley Road Hayes, Middlesex UB3 1HH Hayes, Middlesex UB3 1HH (GB)