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    ASSEMBLY INCLUDING A FLEXIBLE DISK AND A DISKDRIVE THEREFOR
    1.
    发明专利
    ASSEMBLY INCLUDING A FLEXIBLE DISK AND A DISKDRIVE THEREFOR 未知

    公开(公告)号：DE3269244D1

    公开(公告)日：1986-03-27

    申请号：DE3269244

    申请日：1982-11-23

    Applicant: IBM

    Inventor： KEIDL STEVEN DENNIS ,  SHIDLER KARL ALLEN

    IPC: G11B5/596 ,  G11B5/012 ,  G11B5/02 ,  G11B19/12 ,  G11B19/28 ,  G11B21/10 ,  G11B23/36 ,  G11B23/42 ,  G11B27/32 ,  G11B17/02 ,  G11B5/55

    Abstract: Control information for a flexible magnetic desk storage assembky (41, 42) is recorded on the periphery of the disk (42) in a region not used for recording data. The control information is read through the protective cover or envelope (41) which encloses the disk by means of a magnetic transducer (25) such as a four track audia cassette head which bears against the envelope. By recording index and sector pulses as part of the control information, hard sectoring can be inexpensively and accurately achieved. A recorded fixed frequency control signal can be read and used as part of the feedback loop in a phase locked oscillator used to control a d.c. motor driving the spindle. The control information can also include servo tracks which assist in registering the data transducer directly over data tracks on media which has changed its dimensions.

    3.
    发明专利
    未知

    公开(公告)号：DE3770384D1

    公开(公告)日：1991-07-04

    申请号：DE3770384

    申请日：1987-07-31

    Applicant: IBM

    Inventor： BLOCK TIMOTHY ROY ,  ENSTROM MARK RICHARD ,  LUECKE FRANCIS STEPHEN ,  SHIDLER KARL ALLEN ,  SODERSTROM RONALD LEE

    IPC: G11B7/085 ,  G01B9/02 ,  G11B5/55 ,  G11B21/08

    Abstract: In this system the light reflected back over the path (10a) to be measured is fed directly into a semiconductor laser (8a). As is commonly known, the introduction of reflected power through the front, or emitting, facet of the laser actually alters the power present in the laser with an attendant effect on the signal from a photosensor (15) usually located on the rear facet of the laser. The output signal from the photosensor associated with the laser has an asymmetric sawtooth (triangular) waveform. This is in contrast to the output signal from a conventional interferometer which has a sinusoidal waveform. The photosensor output signal is profoundly affected by the return beam. Also unexpectedly, the sawtooth output signal from the photosensor is an essentially linear signal over the range between adjacent fringes. That is, except for the transition at positive and negative peaks. As the path length (10a) of the reflected beam is increased or decreased, the sawtooth output signal changes in a direct linear relationship to the change in path length. This allows precise measurement of changes in distance less than the distance between adjacent fringes.

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