Obtaining a predetermined phase shift in data using different write precompensation associated with different NRZI patterns
AssigneeSeagate Technology LLC
InventorsDrew Michael Mader, Jason Charles Jury, Tim Rausch, Raman Venkataramani
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Abstract
First and second different write precompensation values are associated with different first and second non-return-to-zero, inverted (NRZI) data patterns. The first and second different write precompensation values cause a predetermined phase shift to be written into test data that comprises the first and second NRZI data patterns. The test data is mitten to a recording medium of a storage device using the first and second write precompensation value. The test data is used to determine a response of the storage device to the predetermined phase shift.
Claims18
A method comprising:
- setting first and second different write precompensation values to be associated with different first and second non-return-to-zero, inverted (NRZI) data patterns, the first and second different write precompensation values causing a predetermined phase shift to be written into test data that comprises the first and second NRZI data patterns;
- writing the test data to a recording medium of a storage device using the first and second write precompensation values;
- and
- utilizing the test data to determine an ability to adapt to phase shifts induced by mode hops of a light source of a heat-assisted recording medium based on a response of the storage device to the predetermined phase shift.
An apparatus comprising:
- interface circuitry configured to write data to a magnetic recording medium via a write transducer and read from the magnetic recording medium via a read transducer;
- and
- a controller coupled to the interface circuitry and configured to:
- select first and second write precompensation values associated with respective different first and second non-return-to-zero, inverted (NRZI) data patterns;
- write first and second data segments to the magnetic recording medium using the respective first and second write precompensation values combined with default precompensation values of the data storage device that are intended to compensate for systematically-induced phase shifts, the first and second data segments comprising the respective different first and second NRZI data patterns, the first and second write precompensation values causing the first and second data segments to be written with a predetermined phase shift therebetween;
- and
- read the first and second data segments via the read transducer to test a response of the apparatus to the predetermined phase shift.
A method comprising:
- using a first write precompensation value to write a first set of non-return-to-zero, inverted (NRZI) data patterns to a recording medium of a data storage device;
- using a different, second write precompensation value to write a second set of NRZI data patterns, the first set and the second sets having no NRZI data patterns in common;
- writing test data that comprises patterns from the first and second sets using the respective first and second write precompensation values combined with default precompensation values of the data storage device that are intended to compensate for systematically-induced phase shifts;
- and
- reading the test data to determine a response of the storage device to a predetermined phase shift induced by the first and second write precompensation values.
Dependencies are inferred from the claim text.