Systems and methods for data write loopback based timing control
Systems and methods related to writing data to a storage medium. In some cases, a heat assisted loopback circuit is used that includes: a read circuit, a magnetic write circuit, a heat write circuit, and a loopback circuit. The loopback circuit is operable to selectively couple a derivative of a heat output to a read output and to selectively couple a derivative of a write output to the read output.
1. A method for performing phase alignment in a recording channel, the method comprising:
coupling a write output to a read data;
determining a first delay from the write output to the read data;
coupling a heat output to the read data;
determining a second delay from the heat output to the read data;
calculating a phase delay value corresponding to a difference between the first delay and the second delay; and
modifying a heat data path providing the heat output to delay the heat output by an amount corresponding to the phase delay value.
2. The method of claim 1 , wherein the method further comprises:
providing a write head operable to magnetize a storage medium, wherein a derivative of the write output is operable to excite the write head; and
providing a heat source operable to heat the storage medium, wherein a derivative of the heat output is operable to excite the heat source.
3. The method of claim 2 , wherein the heat source is a laser, and wherein the write is a magneto resistive write head.
4. The method of claim 1 , wherein determining the first delay from the write output to the read data comprises:
writing a pattern via a write data input;
detecting the pattern in the read data; and
determining a delay between a first time corresponding to when the pattern is written via the write data input and a second time corresponding to when the pattern is detected in the read data.
5. The method of claim 4 , wherein the pattern is a 2T pattern.
6. The method of claim 1 , wherein determining the second delay from the heat output to the read data comprises:
writing a pattern via a write data input;
detecting the pattern in the read data; and
determining a delay between a first time corresponding to when the pattern is written via the write data input and a second time corresponding to when the pattern is detected in the read data.
7. The method of claim 1 , wherein the method is performed in a hard disk drive.
8. A method for performing phase alignment in a recording channel, the method comprising:
determining a first delay from a write output to a read data;
coupling a heat output to the read data;
determining a second delay from the heat output to the read data;
calculating a phase delay value corresponding to a difference between the first delay and the second delay; and
modifying a heat data path providing the heat output to delay the heat output by an amount corresponding to the phase delay value.
9. The method of claim 8 , wherein the method further comprises:
providing a write head operable to magnetize a storage medium, wherein a derivative of the write output is operable to excite the write head; and
providing a heat source operable to heat the storage medium, wherein a derivative of the heat output is operable to excite the heat source.
10. The method of claim 9 , wherein the heat source is a laser, and wherein the write is a magneto resistive write head.
11. The method of claim 9 , wherein the method further comprises: coupling the write output to the read data.
12. The method of claim 8 , wherein determining the first delay from the write output to the read data comprises:
writing a pattern via a write data input;
detecting the pattern in the read data; and
determining a delay between a first time corresponding to when the pattern is written via the write data input and a second time corresponding to when the pattern is detected in the read data.
13. The method of claim 12 , wherein the pattern is a 2T pattern.
14. The method of claim 8 , wherein determining the second delay from the heat output to the read data comprises:
writing a pattern via a write data input;
detecting the pattern in the read data; and
determining a delay between a first time corresponding to when the pattern is written via the write data input and a second time corresponding to when the pattern is detected in the read data.
15. A method for performing phase alignment in a recording channel, the method comprising:
determining a first delay from a write output to a read data;
determining a second delay from a heat output to the read data;
calculating a phase delay value corresponding to a difference between the first delay and the second delay; and
modifying a heat data path providing the heat output to delay the heat output by an amount corresponding to the phase delay value.
16. The method of claim 15 , wherein the method further comprises:
providing a write head operable to magnetize a storage medium, wherein a derivative of the write output is operable to excite the write head; and
providing a heat source operable to heat the storage medium, wherein a derivative of the heat output is operable to excite the heat source.
17. The method of claim 16 , wherein the method further comprises:
coupling the write output to the read data; and
coupling the heat output to the read data.
18. The method of claim 16 , wherein the heat source is a laser, and wherein the write is a magneto resistive write head.
19. The method of claim 15 , wherein determining the first delay from the write output to the read data comprises:
writing a pattern via a write data input;
detecting the pattern in the read data; and
determining a delay between a first time corresponding to when the pattern is written via the write data input and a second time corresponding to when the pattern is detected in the read data.
20. The method of claim 19 , wherein the pattern is a 2T pattern.