Clock extraction method for patterned medium, clock extraction circuit for patterned medium and patterned medium
AssigneeFujitsu Limited
InventorHaruhiko Izumi
Life of this patent
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Abstract
Aimed at is to match a timing of a clock signal with a magnetic dot of a patterned medium. A magnetic part arraying magnetic dots for recording a magnetic signal at certain intervals and a nonmagnetic part not recording a magnetic signal are featured in the patterned medium. A position of the nonmagnetic part not recording a magnetic signal is detected by a magnetic head and a clock signal is synchronized with a detection signal of the nonmagnetic part.
Claims18
A clock extraction method for extracting a clock signal determining a timing of writing or reading data to or from a patterned medium, comprising:
- detecting by using a magnetism detection unit a magnetic part arraying magnetic dots at certain intervals for recording a magnetic signal, and a magnetic signal recorded in the patterned medium comprising a nonmagnetic part not recording a magnetic signal;
- and
- identifying a section in which an absolute value of an amplitude of the magnetic signal detected by the magnetism detection unit continuously indicates less than a certain value as the nonmagnetic part, and synchronizing the clock signal with a timing of a start or end of the identified nonmagnetic part or a detection timing of the magnetic signal of the magnetic dot of the magnetic part subsequent to the nonmagnetic part.
A clock extraction method for extracting a clock signal determining a timing of writing or reading data to or from a patterned medium, comprising:
- detecting by using a magnetism detection unit a magnetic signal recorded in a patterned medium comprising a magnetic part arraying magnetic dots at certain intervals for recording a magnetic signal, a zone not recording a magnetic signal and a nonmagnetic part having at least one reference dot recording the magnetic signal;
- and
- detecting by using the magnetism detection unit the magnetic signal of the reference dot in the nonmagnetic part, and synchronizing the clock signal with a timing of the magnetic signal of the reference dot being detected.
A patterned medium, featured with a magnetic part arraying magnetic dots at certain intervals for recording a magnetic signal, and a nonmagnetic part not recording the magnetic signal, both in a track.
A magnetic disk apparatus, comprising:
- a clock signal generation circuit for generating a clock signal determining a timing of writing or reading data to or from a patterned medium;
- a magnetism detection unit for detecting a magnetic signal recorded in a patterned medium comprising a magnetic part arraying magnetic dots at certain intervals for recording a magnetic signal, and a nonmagnetic part not recording a magnetic signal;
- a zero level detection circuit for detecting a zero level at which an absolute value of an amplitude of the magnetic signal detected by the magnetism detection unit becomes less than a certain value;
- and
- a signal extraction circuit for extracting a signal of which a pulse width is equal to or more than a certain value as a nonmagnetic part detection signal which indicates a position of the nonmagnetic part from among a plurality of zero level detection signals detected by the zero level detection circuit, wherein
- the clock signal generation circuit synchronize the clock signal with the nonmagnetic part detection signal.
A magnetic disk apparatus, comprising:
- a clock signal generation circuit for generating a clock signal determining a timing of writing or reading data to or from a patterned medium;
- a magnetism detection unit for detecting a magnetic signal recorded in a patterned medium comprising a magnetic part arraying magnetic dots at certain intervals for recording a magnetic signal, and a nonmagnetic part not recording a magnetic signal;
- a zero level detection circuit for detecting a zero level at which an absolute value of an amplitude of the magnetic signal detected by the magnetism detection unit becomes less than a certain value;
- a signal extraction circuit for extracting a signal of which a pulse width is equal to or more than a certain value as a nonmagnetic part detection signal which indicates a position of the nonmagnetic part from among a plurality of zero level detection signals detected by the zero level detection circuit;
- and
- a slope detection circuit for detecting a timing at which a slope of the magnetic signal detected in the magnetic part becomes zero after the nonmagnetic part detection signal is detected, wherein
- the clock signal generation circuit synchronizes the clock signal with the timing at which the slope of the magnetic signal of the magnetic part becomes zero.
A clock extraction circuit for a patterned medium, comprising:
- a magnetism detection unit for detecting a magnetic signal recorded in a patterned medium comprising a magnetic part arraying magnetic dots at certain intervals for recording a magnetic signal, and a nonmagnetic part not recording a magnetic signal;
- a zero level detection circuit for detecting a zero level at which an absolute value of an amplitude of the magnetic signal detected by the magnetism detection unit becomes less than a certain value;
- a signal extraction circuit for extracting a signal of which a pulse width is equal to or more than a certain value as a nonmagnetic part detection signal which indicates a position of the nonmagnetic part from among a plurality of zero level detection signals detected by the zero level detection circuit;
- and
- a clock signal generation circuit for synchronizing said clock signal with a timing of the nonmagnetic part detection signal or the magnetic signal of the magnetic dot in the magnetic part subsequent to the nonmagnetic part being detected.
Dependencies are inferred from the claim text.