Patent Number: 7,133,229

Title: Magnetic recording disk drive with patterned media and compensation for write-clock timing error caused by rotational disturbances

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.

Inventors: Semba; Tetsuo (San Jose, CA)

Assignee: Hitachi Global Storage Technologies Netherlands B.V.

International Classification: G11B 5/09 (20060101)

Expiration Date: 2019-11-07 0:00:00