Patent ID: 9640210
Date: 2017-05-02
CPC Classifications: G11B

Claim:
1. A method of positioning a write head based on position signals generated from signals read by a read head as the read head crosses a plurality of reference spirals, including first and second spirals that are adjacent, the method comprising: after the read head crosses the first spiral and prior to the read head crossing the second spiral, disabling spiral detection; after disabling the spiral detection and prior to the read head crossing the second spiral, enabling the spiral detection; while the spiral detection is enabled, determining that the read head has crossed the second spiral based on a position signal generated from signals read by the read head, and responsive to the determining, demodulating the position signal to determine a radial position of the write head; disabling spiral detection after a predetermined time period has elapsed since the determination that the read head has crossed the second spiral; and based on the determined radial position, adjusting a radial velocity of the write head.