Positioning control circuit, measurement apparatus for trace information and related method
AssigneeFujitsu Limited
InventorTakayuki Kawabe
Life of this patent
Estimating the term…
Abstract
A magnetic disk apparatus is configured so as to read trace information from a discrete track recording medium recording the trace information for making a servo locus of a magnetic head trace the center line of physical tracks and control the servo locus of the magnetic head onto the center line of the physical tracks.
Claims13
A method for measuring a displacement amount between a center line of a physical track formed in between two guard bands on a discrete track recording (DTR) medium and a servo reference locus of a magnetic head which scans thereon, comprising:
- recording a repeat pattern, which is a repeatedly written magnetized state in data sector zone between each servo, in between the two guard bands;
- scanning repeatedly on the repeat pattern by the magnetic head while shifting a servo locus of the magnetic head in the radial direction of the discrete track recording (DTR) medium in steps from the servo reference locus;
- recording an amplitude variation of a signal reproduced by, and transmitted from, the magnetic head based on the repeat pattern during the scanning;
- and
- determining a displacement amount of the magnetic head from the servo reference locus in terms of an amplitude value which indicates the center of the physical track within the amplitude variation as the displacement amount of the physical track relative to the servo reference locus.
A measurement record apparatus scanning a servo sector and a repeat pattern, which is a repeatedly written magnetized state in a data sector zone between each servo sector, forming zone between the servo sector and next servo sector on a physical track of a discrete track recording (DTR) medium by a magnetic head based on a servo reference locus, comprising:
- a unit for making the magnetic head scan repeatedly on the repeat pattern between the servo sectors while shifting a servo locus of the magnetic head in the radial direction of the discrete track recording (DTR) medium by an increment of a predetermined offset amount from the servo reference locus;
- a unit for recording an amplitude variation of a signal reproduced by, and transmitted from, the magnetic head based on the repeat pattern during the scanning;
- a unit for extracting a displacement amount of the magnetic head from the servo reference locus in terms of an amplitude value which indicates the center of the physical track within the amplitude variation;
- and
- a recording unit for recording the extracted displacement amount in the discrete track recording (DTR) medium.
A positioning control circuit, comprising:
- a demodulation unit for demodulating plural pieces of trace information, which are recorded in a predetermined sequence by each servo sector of a discrete track recording (DTR) medium, in the sequence;
- and
- a control unit for controlling a servo locus of a magnetic head according to the trace information.
A positioning control circuit, comprising:
- a demodulation unit for demodulating trace information from a discrete track recording (DTR) medium;
- and
- a control unit for controlling a servo locus of a magnetic head according to the trace information, wherein
- said demodulation unit demodulates plural pieces of trace information, which are recorded in a predetermined sequence by each servo sector of a discrete track recording (DTR) medium, in the sequence, and
- said control unit reflects, in the aforementioned sequence, the demodulated trace information for each servo sector to a servo locus of a magnetic head which scans in one data sector range.
Dependencies are inferred from the claim text.