Cancelling adjacent track interference signal with different data rate

• US 10,460,762 B1
• Filed: 09/04/2018
• Issued: 10/29/2019
• Est. Priority Date: 09/04/2018
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Wu, Zheng, Bellorado, Jason, Marrow, Marcus, Ashe, Vincent Brendan
• Primary Examiner(s): Dinh, Tan X
• Application Number:
  US16/121,296
• Time in Patent Office: 420 Days
• Field of Search: 360 39, 360 31, 360 27, 360 29, 360 45, 360 48, 360 51, 360 53, 360 55, 360 65, 360 75
• CPC Class Codes: G11B 20/10046 filtering or equalising, e.g. setting the tap weights of an FIR filter
• CPC Class Codes: G11B 20/24 for reducing noise control of amplification in general, e.g. dependent upon noise level H03G
• 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 5/035 Equalising
• CPC Class Codes: G11B 5/54 with provision for moving the head into or out of its operative position or across tracks

Abstract

An apparatus may comprise a circuit configured to receive first underlying data corresponding to a first signal with a first rate and receive a second signal with a second rate corresponding to second underlying data. The circuit may interpolate the first underlying data to generate a plurality of interpolated signals, determine, for the first signal, a first channel pulse response shape with the first rate, and determine an interference component signal based on the plurality of interpolated signals and the first channel pulse response shape. The circuit may then cancel interference in the second signal using the interference component signal to generate a cleaned signal.

Claims

1. An apparatus comprising:

a circuit configured to;

receive first underlying data corresponding to a first signal with a first rate;

receive a second signal with a second rate corresponding to second underlying data;

interpolate the first underlying data to generate a plurality of interpolated signals;

determine, for the first signal, a first channel pulse response shape with the first rate;

determine an interference component signal based on the plurality of interpolated signals and the first channel pulse response shape; and

cancel interference in the second signal using the interference component signal to generate a cleaned signal.

2. The apparatus of claim 1, the circuit further configured to:

receive a third signal with the second rate; and

equalize the third signal to generate the second signal.

3. The apparatus of claim 1, further comprising a detector circuit to generate a bit sequence corresponding to the second underlying data based on the cleaned signal.

4. The apparatus of claim 1, further comprising the circuit further configured to perform the interpolation of the first underlying data to generate a plurality of interpolated signals using a plurality of respective interpolation coefficients stored in a look up table.

5. The apparatus of claim 4, further comprising the circuit further configured to select the plurality of respective interpolation coefficients stored in the look up table based on a fractional portion of a ratio of the first rate and the second rate.

6. The apparatus of claim 5 further comprising the circuit configured to:

generate the plurality of interpolated signals using a plurality of respective finite impulse response filters using the plurality of respective interpolation coefficients as filter coefficients of the plurality of respective finite impulse response filters.

7. The apparatus of claim 6 further comprising the circuit configured to:

generate an error signal based on the interference component signal and the second signal; and

perform the determining, for the first signal, of the first channel pulse response shape with the first rate using least mean square (LMS) adaptation based on the error signal.

8. The apparatus of claim 4 further comprising the circuit configured to determine the interference component signal based on the first underlying data and the first channel pulse response shape at least in part by applying the first channel pulse response shape to the plurality of interpolated signals.

9. The apparatus of claim 1, further comprising the second signal corresponding to a track of interest of a hard drive media with a first channel bit density and the first signal corresponding to an adjacent track to the track of interest with a second channel bit density.

10. A system comprising:

a cancellation circuit configured to;

receive first underlying data corresponding to a first signal with a first rate;

interpolate the first underlying data to generate a plurality of interpolated signals;

determine, for the first signal, a first channel pulse response shape with the first rate; and

determine an interference component signal based on the plurality of interpolated signals and the first channel pulse response shape; and

an adder configured to;

receive a second signal with a second rate corresponding to second underlying data; and

cancel interference in the second signal using the interference component signal to generate a cleaned signal.

11. The system of claim 10 further comprising:

an equalizer circuit configured to receive a third signal with the second rate and to equalize the third signal to generate the second signal.

12. The system of claim 11 further comprising:

a detector circuit configured to generate a bit sequence based on the cleaned signal.

13. The system of claim 12 further comprising the cancellation circuit further comprising:

an interpolator circuit further configured to generate the plurality of interpolated signals using a plurality of respective interpolation coefficients stored in a look up table.

14. The system of claim 13 further comprising the interpolator circuit further configured to:

select the plurality of respective interpolation coefficients stored in the look up table based on a fractional portion of a ratio of the first rate and the second rate; and

generate the plurality of interpolated signals using a plurality of respective finite impulse response filters using the plurality of respective interpolation coefficients as filter coefficients of the plurality of respective finite impulse response filters.

15. The system of claim 14 further comprising the cancellation circuit including:

a second adder configured to generate an error signal based on the interference component signal and the second signal; and

a channel pulse response shape circuit configured to perform the determining, for the first signal, of the first channel pulse response shape with the first rate using least mean square (LMS) adaptation based on the error signal.

16. The system of claim 15 further comprising the channel pulse response shape circuit further configured to:

determine the interference component signal based on the first underlying data and the first channel pulse response shape at least in part by applying the first channel pulse response shape to the plurality of interpolated signals.

17. The system of claim 10 further comprising the second signal corresponding to a track of interest of a hard drive media with a first channel bit density and the first signal corresponding to an adjacent track to the track of interest with a second channel bit density.

18. A method comprising:

receiving first underlying data corresponding to a first signal with a first rate;

interpolating, by an interpolation circuit, the first underlying data to generate a plurality of interpolated signals using a plurality of respective interpolation coefficients stored in a look up table;

determining, by a channel pulse response shape circuit, for the first signal, a first channel pulse response shape with the first rate;

determining, by the channel pulse response shape circuit, an interference component signal based on the plurality of interpolated signals and the first channel pulse response shape; and

receiving, a second signal with a second rate corresponding to second underlying data; and

canceling interference in the second signal using the interference component signal to generate a cleaned signal.

19. The method of claim 18 further comprising:

generating an error signal based on the interference component signal and the second signal;

the interpolating of the first underlying data to generate the plurality of interpolated signals being performed by;

selecting a plurality of respective interpolation coefficients stored in the look up table based on a fractional portion of a ratio of the first rate and the second rate;

generating the plurality of interpolated signals using the plurality of respective finite impulse response filters using the plurality of respective interpolation coefficients as filter coefficients of the plurality of respective finite impulse response filter; and

the determining, for the first signal, of the first channel pulse response shape with the first rate using least mean square (LMS) adaptation based on the error signal.

20. The method of claim 19 further comprising:

generating, by a detector circuit, a bit sequence corresponding to the second underlying data based on the cleaned signal.