Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Patent
1996-02-06
1998-06-30
Psitos, Aristotelis
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
360 7814, G11B 5596
Patent
active
057742987
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.
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W. A. Herrington and F. E. Mueller, "Quad-Burst PES System for Disk File Servo," IBM Technical Disclosure Bulletin, vol. 21, No. 2, Jul. 1978, pp. 804-805.
Cheung Wayne Leung
Liu Chung Chuan
Mueller Francis Edward
International Business Machines - Corporation
Psitos Aristotelis
Wilson James T.
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