Systems and methods for mitigating data interference in a contact signal
View Patent ↗The present inventions are related to systems and methods for determining contact between two elements, and more particularly to systems and methods for determining contact between a head assembly and a storage medium.
1. A storage device, the storage device comprising:
a read/write head assembly disposed in relation to a storage medium, wherein the read/write head assembly includes a sensor operable to provide a sensor output indicating contact between the read/write head assembly and the storage medium and a write head; and
an interference mitigated touch down circuit operable to:
estimate an interference in the sensor output from the write head, wherein estimating the interference in the sensor output includes calculating a coherent output based upon two or more instances of the sensor output; and
remove the interference from the sensor output to yield a filtered output.
2. The storage device of claim 1 , wherein the storage device further comprises:
the storage medium.
3. The storage device of claim 1 , wherein the interference mitigated touch down circuit is further operable to:
determine a contact between the storage medium and the read/write head assembly based on the filtered output; and
provide a contact output.
4. The storage device of claim 1 , wherein estimating the interference in the sensor output further comprises:
calculating a least mean squared value based at least in part on the coherent output.
5. The storage device of claim 4 , wherein the coherent output is a running average of the two or more instances of the sensor output.
6. The storage device of claim 4 , wherein estimating the interference in the sensor output further comprises:
transforming the dimension of the coherent output from a first space to a second space; and
wherein calculating a least mean squared value is based at least in part on the coherent output transformed to the second space.
7. The storage device of claim 6 , wherein the first dimension is a power of P.
8. The storage device of claim 7 , wherein the value of P is nine.
9. The storage device of claim 1 , wherein removing the interference from the sensor output comprises:
subtracting the interference from the sensor output to yield the filtered output.
10. The storage device of claim 1 , wherein the interference mitigated touch down circuit is implemented as part of a semiconductor device.
11. The storage device of claim 1 , wherein the storage device is a hard disk drive.
12. The storage device of claim 1 , wherein the sensor output changes as a function of a temperature of the read/write head assembly.
13. A contact detection system, the system comprising:
an interference mitigated touch down circuit operable to:
receive a sensor output indicating a contact between a read/write head assembly and a storage medium;
estimate an interference in the sensor output from a write head included in the read/write head assembly, wherein estimating the interference in the sensor output includes:
calculating a coherent output based upon two or more instance of the sensor output; and
calculating a least mean squared value based at least in part on the coherent output; and
remove the interference from the sensor output to yield a filtered output.
14. The contact detection system of claim 13 , wherein the contact detection system is implemented as part of a semiconductor device.
15. The contact detection system of claim 13 , wherein the contact detection system is implemented as part of a storage device, and wherein the storage device further comprises:
a storage medium; and
a read/write head assembly disposed in relation to the storage medium, wherein the read/write head assembly includes a sensor operable to provide the sensor output indicating contact between the read/write head assembly and the storage medium.
16. The contact detection system of claim 13 , wherein the interference mitigated touch down circuit is further operable to:
determine a contact between the storage medium and the read/write head assembly based on the filtered output; and
provide a contact output.
17. The contact detection system of claim 13 , wherein the coherent output is a running average of the two or more instances of the sensor output.
18. The contact detection system of claim 13 , wherein removing the interference from the sensor output comprises:
subtracting the interference from the sensor output to yield the filtered output.
19. A method for contact detection, the method comprising:
providing a read/write head assembly including a contact sensor and a write head;
moving the read/write head a first distance from a storage medium, wherein no contact between the read/write head assembly and the storage medium occurs;
receiving a sensor output from the contact sensor, wherein the sensor output changes as a function of a temperature of the read/write head assembly;
estimating an interference in the sensor output from the write head; and
moving the read/write head a second distance from a storage medium, wherein contact between the read/write head assembly and the storage medium is possible; and
removing the interference from the sensor output to yield a filtered output.
20. The method of claim 19 , wherein estimating the interference in the sensor output comprises:
calculating a coherent output based upon two or more instance of the sensor output; and
calculating a least mean squared value based at least in part on the coherent output.