Dynamic magnetic information storage or retrieval – General processing of a digital signal – Data clocking
Reexamination Certificate
2008-01-29
2008-01-29
Dinh, Tan (Department: 2627)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Data clocking
C360S046000, C360S053000, C360S048000
Reexamination Certificate
active
07324294
ABSTRACT:
A magnetic recording disk drive has a patterned magnetic recording disk with data blocks of magnetizable material separated by nonmagnetic regions, a read head for reading the magnetized data blocks and generating a readback signal, and a timing circuitry that generates from the readback signal a series of timing pulses. When the read head is over a nonmagnetic region the readback signal is significantly reduced, and this signal reduction is detectable to determine the position of the nonmagnetic regions. The timing circuitry includes a rectifier that rectifies the readback signal, a highpass filter that filters the rectified signal at the frequency of the data blocks, and a peak detector that detects the peaks of the filtered signal and generates a series of timing pulses, each pulse representing a nonmagnetic region. The timing pulses can be used for marking the bit boundaries in the digital data sequence that is output from the read channel or as the write clock signal to the write head for magnetizing the data blocks.
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Berthold Thomas R.
Dinh Tan
Hitachi Global Storage Technologies - Netherlands B.V.
Mercedes Dismery
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