(19)

(11)

EP 0 070 305 A1

(12)

(43) Date of publication: 26.01.1983 Bulletin 1983/04 (21) Application number: 82900728.0 (22) Date of filing: 20.01.1982

(51) International Patent Classification (IPC):  G01B 7/ 30( . ) G01D 5/ 245( . ) G01B 21/ 22( . ) H03M 1/ 00( . ) (86) International application number: PCT/US1982/000064 (87) International publication number: WO 1982/002631 (05.08.1982 Gazette 1982/19)

(84) Designated Contracting States: CH DE FR GB LI NL SE (30) Priority: 21.01.1981 US 19810226935 (71) Applicant: ALPHA ELECTRONICS CORPORATION Littleton, CO 80122 (US)	(72) Inventors: HAYS, William A. Jr. Aurora, CO 80013 (US) FRANKE, Ernest A. Parker, CO 80134 (US) GLADDEN, RObert A. Littleton, CO 80120 (US) (74) Representative: Foster, David Martyn, et al  MATHISEN MACARA & CO. The Coach House 6-8 Swakeleys Road Ickenham Uxbridge UB10 8BZ Ickenham Uxbridge UB10 8BZ (GB)