Browse Prior Art Database

Transducer Positioning

IP.com Disclosure Number: IPCOM000084393D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Cannon, MR: AUTHOR

Abstract

In rotary head magnetic recorders and disk recorders, servo signals are recorded on the record medium and sensed by a transducer having a predetermined gap for precisely positioning the transducer with respect to a desired record track location line corresponding to an idealized scan path, such as indicated by arrow C.

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Transducer Positioning

In rotary head magnetic recorders and disk recorders, servo signals are recorded on the record medium and sensed by a transducer having a predetermined gap for precisely positioning the transducer with respect to a desired record track location line corresponding to an idealized scan path, such as indicated by arrow C.

In one technique of such track centering, a set of servo signals is disposed in a parallelogram geometric form wherein the idealized scan path by a gap is represented by arrow C. In servo signal area A, a predetermined number of servo signal cycles are disposed. Likewise, in area C, area B contains unique signals for identifying the center of the servo signal pattern. For track centering, the number of signals in A are counted, as are the number of signals in C. If the count is equal, then the transducer is perfectly centered.

On the other hand, if the transducer is scanning in a low position, as indicated by arrow L, the number of signals counted in area C exceeds the number of signals counted in area A. Accordingly, a suitable position error signal results from enabling apparatus to reposition the medium and transducer toward idealized position C. In a similar manner, if the transducer scan is high, as at H, the number of signals counted in area A exceeds the number of signals counted in area C. The unique signals in B separate the A and C counts.

Amplitude perturbations and dropouts in areas A and C can cause variations in...