Preamble pattern and magnetic recording system using the pattern
AssigneeHitachi, Ltd.
InventorHiroyuki Tsuchinaga
Life of this patent
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Abstract
When jitter-like noise is prominent, sampling-phase control and amplitude control in a preamble pattern region is affected. It is possible to reduce effects of jitter-like noise without increasing the length of the preamble pattern. By altering a preamble pattern from that of a conventional 4T-cycle to 6T-cycle or over, amplitude data at a peak point of a reproduced signal, which is less affected by jitter-like noise, is utilized. Thus, the stability of the amplitude control can be improved. As to the phase control, a shift of the sampling timing is estimated by sample data of one cycle of the preamble pattern, and an acquisition procedure of the timing control is made faster.
Claims9
A magnetic recording system comprising:
- a magnetic-recording medium with data sectors wherein a preamble pattern of a prescribed cycle is recorded;
- a magnetic head to reproduce the preamble pattern;
- and
- a signal-processing circuit to-process data to be recorded in and reproduced from the data sectors, the cycle of the preamble pattern being 6T or longer, T standing for minimum duration of data-recorded bits in the data sectors, and
- the signal-processing circuit including (i) a means for sampling a signal reproduced from the preamble pattern and (ii) a means for correcting the amplitude by using maximum and minimum amplitude values in each cycle of the preamble pattern sampled by the sampling means.
A magnetic recording system comprising:
- a magnetic-recording medium with data sectors wherein a preamble pattern of a prescribed cycle is recorded;
- a magnetic head to reproduce the preamble pattern;
- and
- a signal-processing circuit to process data to be recorded in and reproduced from the data sectors, the signal-processing circuit including (i) a means for sampling a signal reproduced from the preamble pattern, (ii) a means for computing timing gradients proportionate to phase shifts of sampling by using amplitude values taken by the sampling means, and (iii) a means for estimating the phase shift of sampling by using the timing gradients.
A signal-processing circuit comprising:
- a means for sampling a signal reproduced from a preamble pattern;
- a means for computing timing gradients proportionate to phase shifts of sampling by using amplitude values taken by the sampling means;
- and
- a means for estimating the phase shift of sampling by using the timing gradients.
Dependencies are inferred from the claim text.