公开(公告)号：FR2313737A1

公开(公告)日：1976-12-31

申请号：FR7610904

申请日：1976-04-08

Applicant: IBM

Inventor： CASTRO FERNANDO ,  O'DAY RICHARD L

IPC: G11B5/024 ,  G11B5/09 ,  G11B5/53 ,  G11C11/14 ,  G11C7/00

Abstract: The equivalent of D.C. erase in magnetic tape using a rotating head is accomplished by transmitting a time asymmetric square wave across a rotary transformer to the rotating head. The time asymmetry of the square wave in combination with passage of the square waveform across the rotary transformer creates in the rotating head an erase current asymmetric in amplitude about an average value. The short interval of the square wave has a large amplitude in one direction and the long interval portion of the square wave has a short amplitude in the opposite direction. This current signal in the head produces alternately a large flux bubble above the head and a small flux bubble above the head. By maintaining the relative head to tape speed such that the large flux bubble always overlaps the small flux bubble, the tape can be D.C. erased by an asymmetric waveform. A double-ended driving circuit and a single-ended driving circuit are shown for driving across a rotary transformer to the rotating head with the asymmetric waveform.

公开(公告)号：CA1062803A

公开(公告)日：1979-09-18

申请号：CA253440

申请日：1976-05-27

Applicant: IBM

Inventor： CASTRO FERNANDO ,  O'DAY RICHARD L

IPC: G11B5/024 ,  G11B5/09 ,  G11B5/53 ,  G11B5/02

Abstract: ASYMMETRIC ERASE ACROSS A ROTARY TRANSFORMER TO A ROTATING MAGNETIC HEAD The equivalent of D.C. erase in magnetic tape using a rotating head is accomplished by transmitting a time asymmetric square wave across a rotary transformer to the rotating head. The time asymmetry of the square wave in combination with passage of the square waveform across the rotary transformer creates in the rotating head an erase current asymmetric in amplitude about an average value. The short interval of the square wave has a large amplitude in one direction and the long interval portion of the square wave has a short amplitude in the opposite direction. This current signal in the head produces alternately a large flux bubble above the head and a small flux bubble above the head. By maintaining the relative head to tape speed such that the large flux bubble always overlaps the small flux bubble, the tape can be D.C. erased by an asymmetric waveform. A double-ended driving circuit and a single-ended driving circuit are shown for driving across a rotary transformer to the rotating head with the asymmetric waveform.

公开(公告)号：DE2624833A1

公开(公告)日：1976-12-16

申请号：DE2624833

申请日：1976-06-03

Applicant: IBM

Inventor： CASTRO FERNANDO ,  O'DAY RICHARD LEWIS

IPC: G11B5/024 ,  G11B5/09 ,  G11B5/53 ,  G11B5/02 ,  H04N5/78

Abstract: The equivalent of D.C. erase in magnetic tape using a rotating head is accomplished by transmitting a time asymmetric square wave across a rotary transformer to the rotating head. The time asymmetry of the square wave in combination with passage of the square waveform across the rotary transformer creates in the rotating head an erase current asymmetric in amplitude about an average value. The short interval of the square wave has a large amplitude in one direction and the long interval portion of the square wave has a short amplitude in the opposite direction. This current signal in the head produces alternately a large flux bubble above the head and a small flux bubble above the head. By maintaining the relative head to tape speed such that the large flux bubble always overlaps the small flux bubble, the tape can be D.C. erased by an asymmetric waveform. A double-ended driving circuit and a single-ended driving circuit are shown for driving across a rotary transformer to the rotating head with the asymmetric waveform.