Data storage device employing one-dimensional and two-dimensional channels

• US 9,013,821 B1
• Filed: 06/10/2014
• Issued: 04/21/2015
• Est. Priority Date: 06/10/2014
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Chen, Yiming
• Primary Examiner(s): Agustin, Peter Vincent
• Application Number:
  US14/301,326
• Time in Patent Office: 315 Days
• Field of Search: None
• US Class Current: 360/65
• CPC Class Codes: G11B 20/10046 filtering or equalising, e.g. setting the tap weights of an FIR filter

Abstract

A data storage device is disclosed comprising a disk comprising a plurality of data tracks. A first data track is read to generate a first read signal that is sampled to generate first signal samples. A second data track adjacent the first data track is read to generate a second read signal that is sampled to generate second signal samples. The first signal samples and the second signal samples are processed by a first two-dimensional (2D) to one-dimensional (1D) equalizer to generate a first 1D sequence of equalized samples, and by a 2D-to-2D equalizer to generate a 2D sequence of equalized samples. The first 1D sequence of equalized samples are processed using a first 1D detector to detect a first estimated data sequence, and the 2D sequence of equalized samples are processed using a 2D detector to detect a second estimated data sequence.

Claims

1. A data storage device comprising:

a disk comprising a plurality of data tracks;

a head actuated over the disk, the head comprising a plurality of read elements including a first read element and a second read element; and

control circuitry configured to;

read a first data track using the first read element to generate a first read signal;

sample the first read signal to generate first signal samples;

read a second data track adjacent the first data track using the second read element to generate a second read signal;

sample the second read signal to generate second signal samples;

process the first signal samples and the second signal samples using a first two-dimensional (2D) to one-dimensional (1D) equalizer to generate a first 1D sequence of equalized samples;

process the first signal samples and the second signal samples using a 2D-to-2D equalizer to generate a 2D sequence of equalized samples;

process the first 1D sequence of equalized samples using a first 1D detector to detect a first estimated data sequence; and

process the 2D sequence of equalized samples using a 2D detector to detect a second estimated data sequence.

2. The data storage device as recited in claim 1, wherein the second read element is wider than the first read element.

3. The data storage device as recited in claim 1, wherein:

the first 1D detector is configured to generate first probability metrics associated with the first estimated data sequence; and

the 2D detector is configured to process the first probability metrics to detect the second estimated data sequence.

4. The data storage device as recited in claim 3, wherein:

the 2D detector is configured to generate second probability metrics associated with the second estimated data sequence; and

the first 1D detector is configured to process the second probability metrics to detect the first estimated data sequence.

5. The data storage device as recited in claim 4, wherein the first 1D detector and the 2D detector are configured to iterate on the probability metrics at least once.

6. The data storage device as recited in claim 4, wherein the first probability metrics and the second probability metrics are substantially uncorrelated.

7. The data storage device as recited in claim 1, wherein:

the first 1D detector comprises a trellis type detector; and

the 2D detector comprises a trellis type detector.

8. The data storage device as recited in claim 1, wherein the head comprises a third read element and the control circuitry is further configured to:

read a third data track adjacent the second data track using the third read element to generate a third read signal;

sample the third read signal to generate third signal samples;

process the third signal samples and the second signal samples using a second 2D-to-1D equalizer to generate a second 1D sequence of equalized samples;

process the first signal samples, the second signal samples, and the third signal samples using the 2D-to-2D equalizer to generate the 2D sequence of equalized samples; and

process the second 1D sequence of equalized samples using a second 1D detector to detect a third estimated data sequence.

9. A method of operating a data storage device, the method comprising:

reading a first data track using a first read element to generate a first read signal;

sampling the first read signal to generate first signal samples;

reading a second data track adjacent the first data track using a second read element to generate a second read signal;

sampling the second read signal to generate second signal samples;

processing the first signal samples and the second signal samples using a first two-dimensional (2D) to one-dimensional (1D) equalizer to generate a first 1D sequence of equalized samples;

processing the first signal samples and the second signal samples using a 2D-to-2D equalizer to generate a 2D sequence of equalized samples;

processing the first 1D sequence of equalized samples using a first 1D detector to detect a first estimated data sequence; and

processing the 2D sequence of equalized samples using a 2D detector to detect a second estimated data sequence.

10. The method as recited in claim 9, wherein the second read element is wider than the first read element.

11. The method as recited in claim 9, further comprising:

the first 1D detector generating first probability metrics associated with the first estimated data sequence; and

the 2D detector processing the first probability metrics to detect the second estimated data sequence.

12. The method as recited in claim 11, further comprising:

the 2D detector generating second probability metrics associated with the second estimated data sequence; and

the first 1D detector processing the second probability metrics to detect the first estimated data sequence.

13. The method as recited in claim 12, further comprising the first 1D detector and the 2D detector iterating on the probability metrics at least once.

14. The method as recited in claim 12, wherein the first probability metrics and the second probability metrics are substantially uncorrelated.

15. The method as recited in claim 9, wherein:

the first 1D detector comprises a trellis type detector; and

the 2D detector comprises a trellis type detector.

16. The method as recited in claim 9, further comprising:

reading a third data track adjacent the second data track using a third read element to generate a third read signal;

sampling the third read signal to generate third signal samples;

processing the third signal samples and the second signal samples using a second 2D-to-1D equalizer to generate a second 1D sequence of equalized samples;

processing the first signal samples, the second signal samples, and the third signal samples using the 2D-to-2D equalizer to generate the 2D sequence of equalized samples; and

processing the second 1D sequence of equalized samples using a second 1D detector to detect a third estimated data sequence.