公开(公告)号：DE2601449A1

公开(公告)日：1976-09-16

申请号：DE2601449

申请日：1976-01-16

Applicant: IBM

Inventor： HIGHNOTE JERRY LEE ,  O'DAY RICHARD LEWIS

IPC: H01F38/14 ,  G11B5/008 ,  G11B5/03 ,  G11B5/09 ,  G11B15/02 ,  G11B15/04 ,  G11B15/12 ,  G11B15/14 ,  G11B20/16 ,  G11B5/02 ,  G11B5/12 ,  G11B5/52 ,  H04N5/78

Abstract: A rotating head magnetic tape unit having a fixed stator and a rotating rotor is disclosed. A plurality of transformers are positioned between the rotor and the stator so as to establish an interface for the transmission of electrical signals. Circuit means is provided on the rotor of the rotating head magnetic unit for reclocking data phase shifted by the transformer interface, for protecting against inadvertent write on a magnetic tape, and for synchronizing the clock with the data in a write driver whereby the clock may be used as A.C. bias for the written signal. An N times data frequency clock signal received on the rotor is divided N/2 to obtain the reclocking signals. With regard to the synchronization between the clock and write driver, the N times data frequency clock on the rotor is synchronized on the write driver with the data to accomplish A.C. bias recording.

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.

公开(公告)号：AU6061373A

公开(公告)日：1975-03-27

申请号：AU6061373

申请日：1973-09-24

Applicant: IBM

Inventor： O'DAY RICHARD LEWIS ,  SHELLEDY FRANK BOYD

IPC: G01R33/09 ,  G11B5/02 ,  G11B5/03 ,  G11B5/39 ,  H01F1/00 ,  G11B5/30 ,  G11B5/34

Abstract: A magnetic transducer exhibiting the magnetoresistive (MR) effect includes at least two thin film layers. A three-legged MR film in electrical contact with a higher resistivity layer is magnetically biased by a portion of the MR sense current shunted through the nonmagnetic layer. The need for an accurate and stable bias to reduce distortion is eliminated by subjecting similar adjacent MR elements to opposite currents. Each element is then symmetrically and oppositely biased so that a differential resistance sensing circuit provides an output signal relatively immune to distortion.

公开(公告)号：DE2349423A1

公开(公告)日：1974-04-18

申请号：DE2349423

申请日：1973-10-02

Applicant: IBM

Inventor： BROCK GEORGE WILLIAM ,  O'DAY RICHARD LEWIS ,  SHELLEDY FRANK BOYD

IPC: G01R33/09 ,  G11B5/39 ,  G01R33/02