Data storage device calibrating laser write power for heat assisted magnetic recording
First Claim
1. A data storage device comprising:
- a disk;
a head actuated over the disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk; and
control circuitry configured to;
apply a first write power to the laser and write a first test pattern to the disk;
read the first test pattern while the head crosses over a width of the first test pattern to generate a first read signal;
generate a first track width metric based on the first read signal;
generate a first peak amplitude based on the first read signal;
apply a second write power to the laser and write a second test pattern to the disk;
read the second test pattern while the head crosses over a width of the second test pattern to generate a second read signal;
generate a second track width metric based on the second read signal;
generate a second peak amplitude based on the second read signal;
process the first track width metric, the first peak amplitude, the second track width metric, and the second peak amplitude to estimate a coefficient C of an error function (erf);
PeakAmplitude=Amax*erf(TrackWidthMetric/C)where A max represents a maximum peak amplitude; and
calibrate an operating write power for the laser based on the estimated coefficient C of the error function.
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Accused Products
Abstract
A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a laser configured to heat the disk during write operations. A first test pattern written at a first laser power is read to generate a first track width metric and a first peak amplitude. A second test pattern written at second laser power is read to generate a second track width metric and a second peak amplitude. The first track width metric, the first peak amplitude, the second track width metric, and the second peak amplitude are processed to estimate a coefficient C of an error function. An operating write power for the laser is calibrated based on the estimated coefficient C of the error function.
466 Citations
18 Claims
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1. A data storage device comprising:
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a disk; a head actuated over the disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk; and control circuitry configured to; apply a first write power to the laser and write a first test pattern to the disk; read the first test pattern while the head crosses over a width of the first test pattern to generate a first read signal; generate a first track width metric based on the first read signal; generate a first peak amplitude based on the first read signal; apply a second write power to the laser and write a second test pattern to the disk; read the second test pattern while the head crosses over a width of the second test pattern to generate a second read signal; generate a second track width metric based on the second read signal; generate a second peak amplitude based on the second read signal; process the first track width metric, the first peak amplitude, the second track width metric, and the second peak amplitude to estimate a coefficient C of an error function (erf);
PeakAmplitude=Amax*erf(TrackWidthMetric/C)where A max represents a maximum peak amplitude; and calibrate an operating write power for the laser based on the estimated coefficient C of the error function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of operating a data storage device, the method comprising:
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applying a first write power to a laser of a head and writing a first test pattern to a disk; reading the first test pattern while the head crosses over a width of the first test pattern to generate a first read signal; generating a first track width metric based on the first read signal; generating a first peak amplitude based on the first read signal; applying a second write power to the laser and writing a second test pattern to the disk; reading the second test pattern while the head crosses over a width of the second test pattern to generate a second read signal; generating a second track width metric based on the second read signal; generating a second peak amplitude based on the second read signal; processing the first track width metric, the first peak amplitude, the second track width metric, and the second peak amplitude to estimate a coefficient C of an error function (erf);
PeakAmplitude=Amax*erf(TrackWidthMetric/C)where A max represents a maximum peak amplitude; and calibrating an operating write power for the laser based on the estimated coefficient C of the error function. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification