公开(公告)号：GB2284688A

公开(公告)日：1995-06-14

申请号：GB9423247

申请日：1994-11-17

Applicant: IBM

Inventor： MUELLER FRANCIS EDWARD ,  CHEUNG WAYNE LEUNG ,  LIU CHUNG CHUAN

IPC: G11B5/596 ,  G11B21/08 ,  G11B21/10

Abstract: A digital servo control system for a disk drive provides asynchronous servo information signal demodulation. The system includes a digital demodulator having a digital squarer 164 that removes any phase component of the digitized servo information signal and includes a burst signal accumulator 168 that accumulates the squared terms according to respective burst timing intervals to produce a digital, quadrature position error signal (PES). The demodulator also can include a filter 154 comprising a harmonic notch filter preferably implemented as a Hilbert Transform filter. In another embodiment the demodulator does not include a filter and squarer and, instead, the squarer comprises a sum-and-squarer that sums the squares of odd and even digitized samples. A split burst servo pattern for the servo control system is comprised of half-width transitions that can be written in a single pass of a recording head and therefore has no phase misalignment between adjacent flux patterns.

公开(公告)号：GB2284688B

公开(公告)日：1997-12-10

申请号：GB9423247

申请日：1994-11-17

Applicant: IBM

Inventor： MUELLER FRANCIS EDWARD ,  CHEUNG WAYNE LEUNG ,  LIU CHUNG CHUAN

IPC: G11B5/596 ,  G11B21/08 ,  G11B21/10

Abstract: A digital servo control system for a disk drive provides asynchronous servo information signal demodulation. The system includes a digital demodulator having a digital squarer that removes any phase component of the digitized servo information signal and includes a burst signal accumulator that accumulates the squared terms according to respective burst timing intervals to produce a digital, quadrature position error signal (PES). The demodulator also can include a filter comprising a harmonic notch filter preferably implemented as a Hilbert Transform filter. Alternatively, the demodulator does not include a filter and squarer and, instead, the squarer comprises a sum-and-squarer that sums the squares of odd and even digitized samples. A split burst servo pattern for the servo control system is comprised of half-width transitions that can be written in a single pass of a recording head and therefore has no phase misalignment between adjacent flux patterns.

公开(公告)号：DE3374729D1

公开(公告)日：1988-01-07

申请号：DE3374729

申请日：1983-09-20

Applicant: IBM

Inventor： DOST MARTIN HANS-ULRICH ,  LIU CHUNG CHUAN ,  MUELLER FRANCIS EDWARD

IPC: G05D3/12 ,  G11B5/596 ,  G11B21/10 ,  G11B5/58

Abstract: A track-seeking and track-following servo encodement and detection system employs a servo pattern using a reference signal and control signals, the control signals having an orthogonal phase relationship to each other by cyclically revolving in phase by 90 DEG , 180 DEG , 270 DEG , and repeating this pattern every four tracks.