Data storage device attenuating interference from first spiral track when reading second spiral track
View Patent ↗A data storage device is disclosed comprising a disk surface comprising a first spiral track at least partially overwritten by a second spiral track, and a head actuated over the disk surface based on the second spiral track. The first spiral track comprises a periodic pattern written at a first frequency, and the second spiral track comprises a periodic pattern written at a second frequency different from the first frequency.
1. A data storage device comprising:
a disk surface comprising a first spiral track at least partially overwritten by a second spiral track;
a head actuated over the disk surface; and
control circuitry configured to servo the head over the disk surface based on the second spiral track;
wherein:
the first spiral track comprises a periodic pattern written at a first frequency; and
the second spiral track comprises a periodic pattern written at a second frequency different from the first frequency.
2. The data storage device as recited in claim 1 , wherein a ratio between the first frequency and the second frequency is substantially an integer plus one-half.
3. The data storage device as recited in claim 1 , wherein a ratio between the second frequency and the first frequency is substantially an integer plus one-half.
4. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to:
generate a read signal while reading the second spiral track; and
filter the read signal based on the second frequency to attenuate crosstalk caused by the first spiral track.
5. The data storage device as recited in claim 4 , wherein the control circuitry is further configured to bandpass filter the read signal proximate the second frequency.
6. The data storage device as recited in claim 4 , wherein:
the first spiral track consists of the first periodic pattern; and
the second spiral track comprises a sync mark periodically interrupting the second periodic pattern.
7. The data storage device as recited in claim 1 , wherein:
the first spiral track consists of the first periodic pattern; and
the second spiral track comprises a sync mark periodically interrupting the second periodic pattern.
8. A method of operating a data storage device, the method comprising servoing a head over a disk surface based on a second spiral track on the disk surface, wherein:
a first spiral track on the disk surface is at least partially overwritten by the second spiral track;
the first spiral track comprises a periodic pattern written at a first frequency; and
the second spiral track comprises a periodic pattern written at a second frequency different from the first frequency.
9. The method as recited in claim 8 , wherein a ratio between the first frequency and the second frequency is substantially an integer plus one-half.
10. The method as recited in claim 8 , wherein a ratio between the second frequency and the first frequency is substantially an integer plus one-half.
11. The method as recited in claim 8 , further comprising:
generating a read signal while reading the second spiral track; and
filtering the read signal based on the second frequency to attenuate crosstalk caused by the first spiral track.
12. The method as recited in claim 11 , further comprising bandpass filtering the read signal proximate the second frequency.
13. The method as recited in claim 11 , wherein:
the first spiral track consists of the first periodic pattern; and
the second spiral track comprises a sync mark periodically interrupting the second periodic pattern.
14. The method as recited in claim 8 , wherein:
the first spiral track consists of the first periodic pattern; and
the second spiral track comprises a sync mark periodically interrupting the second periodic pattern.