Zone based timing recovery for bit patterned media

• US 7,729,074 B2
• Filed: 06/28/2007
• Issued: 06/01/2010
• Est. Priority Date: 06/28/2007
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Sankaranarayanan, Sundararajan, Erden, Mehmet Fatih, Venkataramani, Raman Chatapuram
• Primary Examiner(s): Tzeng; Fred
• Application Number:
  US11/770,181
• Publication Number:
  US 20090002865A1
• Time in Patent Office: 1,069 Days
• Field of Search: 360/51, 360/55, 360/47, 360/48, 360/135, 360/77.08, 360/31, 360/40, 428/846.3, 428/848.5
• US Class Current: 360/51
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/59616 Synchronisation; Clocking G11B5/59622 takes precedence
• CPC Class Codes: G11B 5/743 Patterned record carriers, wherein the magnetic recording layer is patterned into magnetic isolated data islands, e.g. discrete tracks
• CPC Class Codes: G11B 5/746 Bit Patterned record carriers, wherein each magnetic isolated data island corresponds to a bit

Abstract

A method includes: producing a bit detection signal in response to a plurality of islands located in a plurality of zones of a bit patterned media, processing the bit detection signal to produce a synchronization signal, wherein the processing is dependent on characteristics of the islands in the zone containing the plurality of islands, and using the synchronization signal to control timing of writing to the bit patterned media. The synchronization signal can also be used to control timing of reading from the bit patterned media.

Claims

1. A method comprising:

producing a bit detection signal in response to a plurality of islands located in a plurality of zones of a bit patterned media, wherein the islands in each of the zones have similar physical characteristics;

producing a zone information signal in response to the physical characteristics of the islands in the zones;

processing the bit detection signal to produce a synchronization signal, wherein the processing is dependent on the zone information signal; and

using the synchronization signal to control timing of writing to the bit patterned media.

2. The method of claim 1, further comprising:

sampling the bit detection signal to produce a sampled signal; and

controlling timing of the sampling in response to the zone information signal.

3. The method of claim 1, further comprising:

sampling the bit detection signal to produce a sampled signal; and

equalizing the sampled signal in response to the zone information signal.

4. The method of claim 1, further comprising:

sampling the bit detection signal to produce a sampled signal;

equalizing the sampled signal to produce an equalized signal; and

detecting the equalized signal in response to the zone information signal.

5. The method of claim 1, further comprising:

sampling the bit detection signal to produce a sampled signal;

equalizing the sampled signal to produce an equalized signal;

detecting the equalized signal to produce an output signal; and

detecting error between the equalized signal and the output signal in response to the zone information signal.

6. The method of claim 1, wherein the zones are located in rings on the bit patterned media.

7. The method of claim 1, wherein different zones have different nominal values for bit width.

8. The method of claim 1, wherein different zones have different jitter noise statistics.

9. The method of claim 1, wherein different zones have different nominal values for island widths.

10. An apparatus comprising:

a bit pattern sensor for producing a bit detection signal in response to a plurality of islands located in a plurality of zones of a bit patterned media, wherein the islands in each of the zones have similar physical characteristics;

circuitry for receiving a zone information signal representative of the physical characteristics of the islands in the zones, and for processing the bit detection signal to produce a synchronization signal, wherein the processing is dependent on the zone information signal; and

a write driver for using the synchronization signal to control timing of writing to the bit patterned media.

11. The apparatus of claim 10, wherein the circuitry comprises:

a sampler for sampling the bit detection signal to produce a sampled signal; and

a voltage controlled oscillator for controlling timing of the sampling in response to the zone information signal.

12. The apparatus of claim 10, wherein the circuitry comprises:

a sampler for sampling the bit detection signal to produce a sampled signal; and

an equalizer for equalizing the sampled signal in response to the zone information signal.

13. The apparatus of claim 10, wherein the circuitry comprises:

a sampler for sampling the bit detection signal to produce a sampled signal;

an equalizer for equalizing the sampled signal to produce an equalized signal; and

a detector for detecting the equalized signal in response to the zone information signal.

14. The apparatus of claim 10, wherein the circuitry comprises:

a sampler for sampling the bit detection signal to produce a sampled signal;

an equalizer for equalizing the sampled signal to produce an equalized signal;

a first detector for detecting the equalized signal to produce an output signal; and

a second detector for detecting errors between the equalized signal and the output signal in response to the zone information signal.

15. The apparatus of claim 10, wherein the zones are located in rings on the bit patterned media.

16. The apparatus of claim 10, wherein different zones have different nominal values for bit width.

17. The apparatus of claim 10, wherein different zones have different jitter noise statistics.

18. The apparatus of claim 10, wherein different zones have different nominal values for island widths.