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公开(公告)号：CA1135407A
公开(公告)日：1982-11-09
申请号：CA363461
申请日：1980-10-20
Applicant: IBM
Inventor： CHEATHAM SAMUEL D , HAYNES MUNRO K
Abstract: STABILIZED RECORDING A first signal to be stabilized in a magnetic record member is recorded via a head having a given maximal gap length and pole pieces of high saturation induction. After the first signal is recorded, the magnetic record member is surface erased for stabilizing the just recorded signal. In a preferred form, the surface erasing is performed by AC erasing via a transducer having a gap length less than said maximal gap length. The pole pieces of the erasing head need not have the high saturation induction of the first mentioned head. After such stabilization, signals can be easily recorded and recovered from the magnetic record member by using transducers with gap lengths less than such given maximal gap length and using the normal ferrite heads having a lower saturation induction than the first mentioned heads. The first signal can be advantageously employed as a position indicating signal in a magnetic record member, such as a storage disk or tape. The first signal can also be used for other purposes, such as phase control for recording and in a controlled access or security system. BO978039
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公开(公告)号：FR2410861A1
公开(公告)日：1979-06-29
申请号：FR7831283
申请日：1978-10-31
Applicant: IBM
Inventor： CHEATHAM SAMUEL D , ROBINSON NEIL L , SMATHERS EDMOND W
Abstract: An AC magnetic erase head having improved AC erase characteristics, the magnetic head being formed of two half core elements of a magnetic material, preferably ferrite, defining an irregular edged or jagged-edged gap, and including a non-magnetic substance, preferably glass, within the gap. The magnetic head is preferably produced by thermally etching ferrite magnetic material forming the half core elements by means of relatively prolonged heat soak at an elevated temperature.
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公开(公告)号：CA1119720A
公开(公告)日：1982-03-09
申请号：CA309374
申请日：1978-08-15
Applicant: IBM
Inventor： CHEATHAM SAMUEL D , ROBINSON NEIL L , SMATHERS EDMOND W
Abstract: An AC magnetic erase head having improved AC erase characteristics, the magnetic head being formed of two half core of a magnetic material, preferably ferrite, defining an irregular edged or jagged-edged gap, and including a non-magnetic substance, preferably glass, within the gap. The magnetic head is preferably produced by thermally etching ferrite magnetic material forming the half core elements by means of relatively prolonged heat soak at an elevated temperature.
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