Prediction and cancellation of cage frequency in a disc drive
AssigneeSeagate Technology LLC
InventorsShuang Quan Min, Kian Keong Ooi, Ricky WeiWatt Yeo, Chiap Heok Ang, Ming Zhong Ding, Beng Wee Quak
Life of this patent
Estimating the term…
Abstract
A method for writing servo information to a disc rotatably mounted to a spindle motor. A measured cage frequency is obtained from a written reference track, from which an actual cage frequency is predicted. The predicted cage frequency is then used to derive compensated position commands. During a servo write interval, the compensated position commands are used to control the head such that the head follows the disc movements caused by the cage frequency.
Claims16
A method for writing servo information to a disc rotatably mounted to a spindle motor, the method comprising steps of:
- (a) obtaining a measured cage frequency from a reference track;
- (b) predicting a cage frequency based on the measured cage frequency;
- (c) deriving compensated position commands based on the predicted cage frequency obtained in step (b);
- and
- (d) during a servo write interval, writing servo information to the disc using the compensated position commands.
An apparatus comprising:
- at least one disc mounted for rotational motion;
- at least one head, each head being configured to write to and read from a disc;
- means for predicting and canceling cage frequency as the head writes servo patterns to the disc.
Dependencies are inferred from the claim text.