| 摘要 |
Quality of record readback operations on a real time basis is used as pointers to possible error conditions. The pointers are combined with error detecting and correcting coding schemes, preferably of the residue type, for detecting and correcting large numbers of errors in a group of data bits. The data and check bits are preferably organized in a geometric array in a self-clocking record system of the magnetic media type, the data within check bits are uncoded run-length-limited code. During readback, the run-length-limited code is first converted to data and check bits, then error detection and correction is effected using the pointers. Validity of the run-length-limited code is used as an additional pointer. Examples of marginal operation pointers are excessive phase shift in the readback signal, undesired amplitude deviations in the readback signal, undesired velocity variations in the record system and incorrect wavelengths.
|
