公开(公告)号：US3562635A

公开(公告)日：1971-02-09

申请号：US3562635D

申请日：1968-10-16

Applicant: IBM

Inventor： PARKER GERALD R

IPC: B01J27/224 ,  C07C17/156 ,  G01N27/90 ,  G01R33/12

CPC classification number: G01N27/90 ,  B01J27/224 ,  C07C17/156 ,  C07C19/045

Abstract: This invention detects tape defects down to and in the order of 10-5 inches in diameter or depth. This detection is achieved by recording DC test signals that do not saturate the tape, but instead provide a gradient of DC magnetization through the tape. The detection of very small or very shallow defects is further enhanced by use of an integrating amplifier in the faultdetecting circuit connected to the test read head. The output of the integrating amplifier is a signal which is very similar to the surface appearance of the tape.

公开(公告)号：US3478255A

公开(公告)日：1969-11-11

申请号：US3478255D

申请日：1966-09-06

Applicant: IBM

Inventor： PARKER GERALD R ,  VERDIBELLO AMBROSE A

IPC: G01R33/12 ,  G11B20/10 ,  G11B5/46

CPC classification number: G11B20/10009 ,  G01R33/1207

公开(公告)号：CA1017462A

公开(公告)日：1977-09-13

申请号：CA198773

申请日：1974-05-02

Applicant: IBM

Inventor： COLLINS ROBERT H ,  LEVINE RICHARD F ,  NORTH WILLIAM D ,  O'ROURKE GERALD D ,  PARKER GERALD R

IPC: H01L29/78 ,  H01L21/283 ,  H01L29/00 ,  H01L29/51 ,  H01L29/76