Clock extraction method for patterned medium and circuit thereof
AssigneeFujitsu Limited
InventorHaruhiko Izumi
Life of this patent
Estimating the term…
Abstract
Aimed at is to match a timing of a clock signal with a magnetic dot of a patterned medium. A point at which an amplitude of a reproduction waveform becomes zero or a point at which an amplitude of a magnetic signal changes from the positive to negative or from the negative to positive is detected, and a zero level detection signal or zero-cross detection signal is output to a clock generation circuit which then synchronizes a clock signal with the zero level detection signal or zero-cross detection signal. This enables a matching of the clock signal with a magnetic dot.
Claims17
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 the patterned medium arraying magnetic dots at certain intervals for recording the magnetic signal;
- detecting a timing at which an absolute value of an amplitude of the magnetic signal detected by the magnetism detection unit is equal to or smaller than a certain value;
- and
- synchronizing the clock signal with the timing.
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 the patterned medium arraying magnetic dots at certain intervals for recording the magnetic signal;
- detecting a zero-cross point at which an amplitude of the magnetic signal detected by the magnetism detection unit changes from the positive to negative, or from the negative to positive;
- and
- synchronizing the clock signal with the zero-cross point.
A clock extraction circuit for a patterned medium comprising:
- a clock signal generation circuit for generating a clock signal determining a timing of writing or reading data to or from the patterned medium;
- a magnetism detection unit for detecting a magnetic signal recorded in a patterned medium arraying magnetic dots at certain intervals for recording the magnetic signal;
- and
- 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 indicates a certain value or smaller, wherein
- the clock signal is synchronized with the timing of the zero level being detected.
A clock extraction circuit for a patterned medium 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 the patterned medium arraying magnetic dots at certain intervals for recording the magnetic signal;
- and
- a zero-cross detection circuit for detecting a zero-cross point at which an amplitude of the magnetic signal detected by the magnetism detection unit changes from the positive to negative, or from the negative to positive, wherein
- the clock signal is synchronized with the zero-cross point.
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 arraying magnetic dots at certain intervals for recording the magnetic signal;
- and
- 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 indicates a certain value or smaller, wherein
- the clock signal is synchronized with the timing of the zero level being detected.
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 arraying magnetic dots at certain intervals for recording the magnetic signal;
- a zero-cross detection circuit for detecting a zero-cross point at which an amplitude of the magnetic signal detected by the magnetism detection unit changes from the positive to negative, or from the negative to positive, wherein
- the clock signal is synchronized with the zero-cross point.
Dependencies are inferred from the claim text.