Phase detection using sampled data
AssigneeFujitsu Limited
InventorsKatsuhiko Fukuda, Kenichi Hamada, Masakazu Taguchi
Life of this patent
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Abstract
A clock adjustment device for a data reproduction apparatus includes an edge detection part detecting an edge of a reproduced signal corresponding to a predetermined synchronization pattern based on a state of change of sampled values obtained in synchronism with a clock signal from the reproduced signal, a timing signal output part outputting a timing signal in a given cycle determined by the synchronization pattern from a timing at which the edge of the reproduced signal is detected, and a phase adjustment part adjusting a phase of the clock signal when the edge of the reproduced signal is detected and every time the timing signal is output.
Claims22
A clock adjustment device for a data reproduction apparatus for reproducing recorded data from a recording medium in accordance with a maximum likelihood decoding algorithm corresponding to a recording code of partial response by using sampled values obtained by sampling a reproduced signal from the recording medium in synchronism with a clock signal, the reproduced signal corresponding to a predetermined synchronization pattern, the clock adjustment device comprising:
- an edge detection part detecting an edge of the reproduced signal based on a state of change of the sampled values;
- a timing signal output part outputting a timing signal in a given cycle determined by the synchronization pattern from a timing at which the edge of the reproduced signal is detected;
- and
- a phase adjustment part adjusting a phase of the clock signal when the edge of the reproduced signal is detected and every time the timing signal is output.
A data reproduction apparatus for reproducing recorded data from a recording medium in accordance with a maximum likelihood decoding algorithm corresponding to a recording code of partial response by using sampled values obtained by sampling a reproduced signal from the recording medium in synchronism with a clock signal, the reproduced signal corresponding to a predetermined synchronization pattern, the data reproduction apparatus comprising:
- a clock adjustment device,
- the clock adjustment device comprising:
- an edge detection part detecting an edge of the reproduced signal based on a state of change of the sampled values;
- a timing signal output part outputting a timing signal in a given cycle determined by the synchronization pattern from a timing at which the edge of the reproduced signal is detected;
- and
- a phase adjustment part adjusting a phase of the clock signal when the edge of the reproduced signal is detected and every time the timing signal is output.
An edge detection device for detecting an edge of a reproduced signal from a recording medium, the reproduced signal corresponding to a predetermined synchronization pattern, the edge detection device comprising:
- an edge determination part determining, using first through fourth successive sampled values in an order sampled from the reproduced signal and based on a relationship between the first and third sampled values and a relationship between the second and fourth sampled values, whether or not the second or third sampled value corresponds to the edge of the reproduced signal.
A method of detecting an edge of a reproduced signal from a recording medium, the method comprising the steps of:
- (a) obtaining first through fourth successive sampled values in an order sampled from the reproduced signal;
- (b) calculating a first difference between the first and third sampled values and a second difference between the second and fourth sampled values;
- and
- (c) determining whether the second or third sampled value corresponds to the edge of the reproduced signal based on the first and second differences obtained in said step (b).
Dependencies are inferred from the claim text.