DC control of a multilevel signal
AssigneeCalimetrics, Inc.
InventorsDavid C. Lee, John L. Fan, Yung-Cheng Lo
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Abstract
A system and method are disclosed for writing a multilevel data sequence to a storage medium so that a read signal generated by reading the multilevel data sequence from the storage medium will have reduced low frequency content is described. The method includes evaluating the effect of a plurality of candidate merge symbols on an RDS of the read signal. A preferred merge symbol is selected from among the plurality of candidate merge symbols based on the effect of the preferred merge symbol on an RDS of the read signal. The preferred merge symbol is added to the multilevel data sequence so that the RDS of the read signal is controlled.
Claims25
A method of writing a multilevel data sequence to a storage medium so that a read signal generated by reading the multilevel data sequence from the storage medium will have reduced low frequency content comprising:
- evaluating the effect of a plurality of candidate merge symbols on an RDS of the read signal;
- selecting a preferred merge symbol from among the plurality of candidate merge symbols based on the effect of the preferred merge symbol on an RDS of the read signal;
- and
- adding the preferred merge symbol to the multilevel data sequence so that the RDS of the read signal is controlled.
A DC control encoder in a system for writing a multilevel data sequence to a storage medium comprising:
- a processor configured to evaluate the effect of a plurality of candidate merge symbols on an RDS of the read signal and to select a preferred merge symbol from among the plurality of candidate merge symbols based on the effect of the preferred merge symbol on an RDS of a read signal;
- a bit merger configured to add the preferred merge symbol to the multilevel data sequence so that the RDS of the read signal is controlled;
- whereby the read signal generated by reading the multilevel data sequence from the storage medium will have reduced low frequency content.
A storage medium with multilevel data written to the storage medium so that a read signal generated by reading the multilevel data sequence from the storage medium has a reduced low frequency content wherein the multilevel data sequence was written by:
- evaluating the effect of a plurality of candidate merge symbols on an RDS of the read signal;
- selecting a preferred merge symbol from among the plurality of candidate merge symbols based on the effect of the preferred merge symbol on an RDS of the read signal;
- and
- adding the preferred merge symbol to the multilevel data sequence so that the RDS of the read signal is controlled.
Dependencies are inferred from the claim text.