Detecting head/disk contact using timing jitter
View Patent ↗A disk drive that includes a head and a disk. The disk drive also includes a circuit that can detect head/disk contact from a jitter determined from a read signal provided by the head. The jitter may correspond to the time interval between two detected sync marks. Alternatively, the jitter may correspond to a change in frequency of a read clock generated from the read signal. These approaches allow for detection of head movement in a down track direction. Down track is a direction that is essentially parallel with the longitudinal axis of the head.
1. A hard disk drive, comprising:
a disk that includes two separated sync marks;
a head that is coupled to said disk and detects said sync marks; and,
a circuit that is coupled to said head and calculates a jitter from said detected sync marks, said circuit detects a contact between said head and said disk from said jitter.
2. The disk drive of claim 1 , wherein said sync marks are servo sync marks.
3. A method for detecting contact between a head and a disk of a hard disk drive, comprising:
determining two separated sync marks;
a head that makes contact with a disk;
calculating a jitter from the detected sync marks; and, detecting the contact from the jitter.
4. The method of claim 3 , wherein the sync marks are servo sync marks.