Setting optimal boundary thresholds in a decoder for coded signal processing channels

Apparatus for improving data detection reliability in a coded signal processing channel in which digital electrical signals representing digital sample values are generated from analog signals read by a transducer from binary data recorded on a data storage medium, comprising:

• means (308) for storing a plurality of threshold constants whose values define decision boundaries for use in determining whether detected binary data corresponding to a respective coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• means (including 351) for processing binary data on-line for measuring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of the detected binary data that are defined by corresponding Boolean logical expressions;
• means for determining potential error events in the detected binary data (d), comprising two separate counters (M.sub.A, M.sub.B) for counting numbers of times actual values of one of a plurality of linear functions of the digital sample values corresponding to one preselected data pattern are within m.sub.1 units above and corresponding to another preselected data pattern are within m.sub.2 units below, respectively, a preselected one of said boundaries;
• a margin balance counter (C) for accumulating a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• circuitry (376) responsive to a predesignated control event for adjusting the preselected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the last-mentioned count is not greater than a preselected number -S.sub.2.

Apparatus for improving data detection reliability in a coded signal processing channel in which digital electrical signals representing digital sample values are generated from analog signals read by a transducer from binary data recorded on a data storage medium, comprising:

• means (308) for storing a plurality of threshold constants whose values define decision boundaries for use in determining whether detected binary data corresponding to a coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• means (including 351) for processing binary data on-line for measuring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of the detected binary data that are defined by corresponding Boolean logical expressions;
• circuitry (351) for determining potential error events in the detected binary data by generating, for a selected state, first and second outputs (W.sub.above, W.sub.below) corresponding to one preselected data pattern and another preselected related data pattern, respectively, above and below a preselected one of said decision boundaries;
• first and second counters (T.sub.A, T.sub.B) for respectively counting up to preselected numbers N.sub.1 and N.sub.2 total occurrences of said one and another preselected data patterns above and below said preselected one boundary, respectively;
• means (W.sub.above, W.sub.below, 356, D.sub.above, 358, D.sub.below) establishing error margin distances m.sub.1 units above and m.sub.2 units below, respectively, said preselected one boundary;
• third and fourth counters (M.sub.A, M.sub.B) for counting numbers of times actual values of a linear function of digital sample values corresponding to said one and another preselected data patterns are respectively within m.sub.1 units and m.sub.2 units, respectively, of said preselected boundary;
• a margin balance counter (C) for accumulating a count having a magnitude and sign denoting difference between counts in said third and fourth counters;
• and
• circuit means, conditioned by said first and second counters counting to selected numbers N.sub.1 and N.sub.2, respectively, for adjusting the preselected one boundary one unit up or one unit down provided the count in the margin balance counter has reached a preselected number +S.sub.1 or a preselected number -S.sub.2, respectively, where S.sub.1 <N.sub.1 and S.sub.2 <N.sub.2.

Apparatus for improving data detection reliability in a coded signal processing channel comprising:

• a magnetic recording medium;
• a transducer for generating analog signals from digital data recorded on the recording medium;
• means for generating from the analog signals digital signals representing digital sample values;
• means (308) for storing a plurality of threshold constants whose values define decision boundaries for use in determining whether detected binary data corresponding to a coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• means (including 351) for processing binary data on-line for measuring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of the detected binary data that are defined by corresponding Boolean logical expressions;
• means for determining potential error events in the detected binary data (d), comprising two separate counters (M.sub.A, M.sub.B) for counting numbers of times actual values of one of a plurality of linear functions of the digital sample values corresponding to one preselected data pattern are within m.sub.1 units above and corresponding to another preselected data pattern are within m.sub.2 units below, respectively, a preselected one of said boundaries;
• a margin balance counter (C) for accumulating a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• circuitry (376) responsive to a predesignated control event for adjusting the preselected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the latter count is not greater than a preselected number -S.sub.2.

A method for improving data detection reliability in a coded signal processing channel in which digital electrical signals representing digital sample values are generated from analog signals read by a transducer from binary data recorded on a data storage medium, comprising the steps of:

• providing a plurality of threshold constants whose values define initial decision boundaries for use in determining whether detected binary data corresponding to a coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• processing known data corresponding to the detected binary data on-line for measuring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of said known data that are defined by corresponding Boolean logical expressions;
• determining potential error events in the detected binary data by counting in two separate counters numbers of times actual values of one of a plurality of linear functions of the digital sample values corresponding to one preselected data pattern are within m.sub.1 units above and one of a different plurality of linear functions of the digital sample values corresponding to another preselected data pattern are within m.sub.2 units below, respectively, a preselected one of said boundaries;
• accumulating in a margin balance counter a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• responsive to a predesignated event, adjusting the preselected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the last-mentioned count is not greater than a preselected number -S.sub.2 to create an updated decision boundary.

Apparatus for improving data detection reliability in a coded signal processing channel in which digital electrical signals representing digital sample values are generated from analog signals read by a transducer from binary data recorded on a data storage medium, comprising:

• means (308) for storing a plurality of threshold constants whose values define decision boundaries for use in determining whether detected binary data corresponding to a respective coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• means (including 351) for processing known data corresponding to the detected binary data on-line for measuring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of said known data that are defined by corresponding Boolean logical expressions;
• means for determining potential error events in the detected binary data (d), comprising two separate counters (M.sub.A, M.sub.B) for counting numbers of times actual values of one of a plurality of linear functions of the digital sample values corresponding to one preselected data pattern are within m.sub.1 units above and corresponding to another preselected data pattern are within m.sub.2 units below, respectively, a preselected one of said boundaries;
• a margin balance counter (C) for accumulating a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• circuitry (376) responsive to a predesignated control event for adjusting the preselected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the last-mentioned count is not greater than a preselected number -S.sub.2.

A method for improving data detection reliability in a coded signal processing channel in which digital electrical signals representing digital sample values are generated from analog signals read by a transducer from binary data recorded on a data storage medium, comprising the steps of:

• providing a plurality of threshold constants whose values define initial decision boundaries for use in determining whether detected binary data corresponding to a coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• recording known binary data on the storage mediums processing detected binary data on-line for inferring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of the detected binary data and corresponding sequences of the known recorded binary data that are defined by corresponding Boolean logical expressions by
• (i) moving a selected one of the initial decision boundaries upward m.sub.1 units and then downward m.sub.2 units from an initial preselected value, and
• (ii) while the selected boundary is moved (a) upward and then (b) downward, counting in separate counters numbers of times (a) a specific data sequence of the known recorded binary data that should be above the selected boundary is detected as a data sequence below said selected boundary and (b) a specific data sequence of the known recorded binary data that should be below said selected boundary is detected as a data sequence above said selected boundary, respectively;
• accumulating in a margin balance counter a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• responsive to a predesignated event, adjusting the preselected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the last-mentioned count is not greater than a preselected number -S.sub.2 to create an updated decision boundary.

Apparatus for improving data detection reliability in a coded signal processing channel in which digital electrical signals representing digital sample values are generated from analog signals read by a transducer from binary data recorded on a data storage medium, comprising:

• means (308) for storing a plurality of threshold constants whose values define decision boundaries for use in determining whether detected binary data corresponding to a coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• means (including 397, W.sub.above, W.sub.below, 360, 362) for processing detected binary data on-line for inferring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of the detected binary data and corresponding sequences of known recorded binary data that are defined by corresponding Boolean logical expressions;
• means (including 399, 398, 395, 396) operative during detection of binary data corresponding to the known recorded data for moving a selected one of the decision boundaries upward m.sub.1 units and then downward m.sub.2 units from an initial preselected value;
• two separate counters (M.sub.A, M.sub.B) operative while the selected boundary is moved (a) upward and then (b) downward for counting number of times (a) a specific sequence of the detected binary data that should be above the selected boundary is detected as a data sequence below said selected boundary and (b) number of times a sequence of the detected binary data that should be below said selected boundary is detected as a data sequence above said selected boundary, respectively;
• a margin balance counter (C) for accumulating a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• circuitry (376) responsive to a predesignated control event for adjusting the selected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the last-mentioned count is not greater than a preselected number -S.sub.2.

Apparatus for improving data detection reliability in a coded signal processing channel comprising:

• a magnetic recording medium;
• a transducer for generating analog signals from binary data recorded on the recording medium;
• means for generating from the analog signals digital signals representing digital sample values;
• means (308) for storing a plurality of threshold constants whose values define decision boundaries for use in determining whether detected binary data corresponding to a coded sequence of a runlength limited (RLL) code is a "1" or a "0";
• means (including 397, W.sub.above, W.sub.below, 360, 362) for processing detected binary data on-line for inferring error margins at each of a plurality of respective decision boundaries by using an abstract relationship between each preselected decision boundary and specific sequences of the detected binary data and corresponding sequences of known recorded binary data that are defined by corresponding Boolean logical expressions;
• means (including 399, 398, 395, 396) operative during detection of binary data corresponding to the known recorded data for moving a selected one of the decision boundaries upward m.sub.1 units and then downward m.sub.2 units from an initial preselected value;
• two separate counters (M.sub.A, M.sub.B) operative while the selected boundary is moved (a) upward and then (b) downward for counting number of times (a) a specific sequence of the detected binary data that should be above the selected boundary is detected as a data sequence below said selected boundary and (b) number of times a sequence of the detected binary data that should be below said selected boundary is detected as a data sequence above said selected boundary, respectively;
• a margin balance counter (C) for accumulating a count having a magnitude and sign denoting difference between counts in said separate counters;
• and
• circuitry (376) responsive to a predesignated control event for adjusting the selected decision boundary upwardly if the count in the margin balance counter at least equals a preselected number +S.sub.1 or downwardly if the last-mentioned count is not greater than a preselected number -S.sub.2.