Dynamic magnetic information storage or retrieval – General processing of a digital signal – Data clocking
Reexamination Certificate
2006-11-07
2006-11-07
Tzeng, Fred F. (Department: 2627)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Data clocking
Reexamination Certificate
active
07133229
ABSTRACT:
A magnetic recording disk drive has a patterned magnetic recording disk with data blocks of magnetizable material separated by nonmagnetic regions, a write-clock-generation circuit for timing write pulses to the write head, and a rotational vibration sensor that adjusts the timing of the write pulses to correct for errors caused by rotational disturbances to the disk drive. The write-clock-generation circuit receives a reference clock signal synchronized to disk rotation and multiplies it to generate a higher-frequency write-clock signal. The write-clock-generation circuit includes a phase detector that compares the phase of the reference clock signal and the write-clock signal and provides an error signal. The output of the rotational vibration sensor is summed with the phase detector error signal to compensate for disk rotation speed changes caused by rotational disturbances.
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Berthold Thomas R.
Hitachi Global Storage Technologies - Netherlands B.V.
Tzeng Fred F.
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