| 摘要 |
A magnetic disk drive having a disk surface containing circular tracks containing servo transitions, a head positioning system for positioning a servo signal sensor over selected servo tracks, each servo track containing a series of frame radially aligned with the frames in other tracks, each frames containing a synchronizing field. The synchronizing fields contain first and second dibit transitions, the second dibit transitions being contained in every synchronizing field, said second dibit transitions being contained in every synchronizing field in a given track, and the first dibit transitions being contained in fewer than every synchronizing field in the rack, but in at least one of any two successive synchronizing fields. The time period between the sensing of the first and second dibit transitions in a frame is shorter than the time period between the sensing of any other pair of dibit transitions. Sensed dibit transitions are distinguished as first or second dibit transitions according to the time of their sensing relative to one another. The second dibit transitions thus provide synchronization information, and the first dibit transitions provide indexing and track identification information.
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