Data recovery method and apparatus for jitter tolerant peak detected channels
AssigneeEastman Kodak Company
InventorsRobert Earl Swanson, Thomas Daniel Carr
Life of this patent
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Abstract
A data recovery technique for jitter tolerant peak detected channels. The number of consecutive zeros between ones are reproduced in a run-length coded, peak detected channel. The interval (time, distance) is measured between peaks of a run-length encoded digital data signal wherein peaks represent ones and absence of peaks represent zeros. A look-up-table is provided having entries for all possible intervals between peaks for the run-length code used and corresponding entries for the number of zeros between ones. The measured interval is applied to the look-up-table to produce a string of zero bits between one bits.
Claims8
A method of reproducing the number of consecutive zeros in a run-length coded peak detected channel, comprising the steps of:
- measuring the interval between peaks of a run-length encoded digital data signal, wherein a peak represents a one and the absence of a peak represents a zero;
- providing a look-up-table having entries for all possible intervals between peaks for the run-length code used and corresponding entries for the number of zeros between ones;
- applying the measured interval to said look-up table to produce a string of zero bits between said one bits;
- and
- comparing the interval between peaks measured in said measuring step with a predetermined interval and modifying said measured interval as a function of any difference found in said comparing step.
Apparatus for reproducing the number of consecutive zeros in a run-length coded peak detected channel, comprising:
- a measuring circuit for measuring the interval between peaks of a run-length encoded digital data signal, wherein a peak represents a one and the absence of a peak represents a zero;
- a look-up-table connected to said measuring circuit and having entries for all possible intervals between peaks for the run-length code and corresponding entries for the number of zeros between ones;
- wherein application of the measured interval produced by said measuring circuit to said look-up-table produces a string of zeros between peaks corresponding to said measured distance;
- and
- wherein said measuring circuit includes a high frequency clock and a counter coupled to said clock, such that consecutive peaks of a digital data signal reset said counter to produce a digital signal which is representative of the interval between peaks and which is applied as an address to said look-up-table.
Apparatus for reproducing the number of consecutive zeros in a run length coded peak detected channel, comprising:
- a high resolution clock;
- an interval counter connected to said clock for counting pulses produced by said clock and having a reset;
- a look-up-table connected to said clock having entries for all possible intervals between peaks for a run length coded digital data signal and corresponding entries for the number of zeros between ones;
- and
- means for applying a run-length encoded digital data signal having peaks representing ones and absence of peaks representing zeros, wherein the count of said counter between reset peaks is representative of the interval between peaks and wherein said output of said interval counter is applied as an address to said look-up-table to produce a string of zeros.
Dependencies are inferred from the claim text.