US 6,643,090 B1 · Multi-mode servo position error signal demodulator circuit

Abstract

Apparatus and method for positioning a head adjacent tracks on a recording surface in a disc drive. A servo control circuit includes a multi-mode servo position error signal (PES) demodulator circuit having an operand generator which outputs operand values from decoded servo position data transduced by the head from the disc surface, and a PES generator which generates a PES indicative of head position with respect to the disc surface in accordance with a selected PES mode from a population of mutually exclusive PES modes each derived from a different combination of selected operand values. A programmable servo processor outputs a current adjustment signal to adjust the current applied to an actuator motor in relation to the PES and a desired position. The servo processor selectably configures the PES generator for each track so that different PES modes are used for different tracks.

Claims17

Dependent claims

A servo circuit configured for use in a disc drive to apply current to an actuator motor to position a head adjacent tracks defined on a disc surface, comprising:

an operand generator which outputs operand values from decoded servo position data transduced by the head from the disc surface;
a position error signal (PES) generator which generates a PES as a sequence of PES samples indicative of head position with respect to the disc surface in accordance with a selected PES mode from a population of mutually exclusive PES modes each derived from a different combination of selected operand values;
and
a servo processor coupled to the PES generator which outputs a corresponding sequence of current adjustment signal samples to adjust the current applied to the actuator motor in relation to the PES and a desired position, wherein the servo processor selectably configures the PES generator so that different ones of the population of mutually exclusive PES modes are used for different tracks on the disc surface.

1 more element

A method for positioning a head adjacent tracks defined on a recording surface of a disc drive, comprising steps of:

(a) defining a population of mutually exclusive PES modes each derived from a different combination of selected operand values obtained in turn from servo position data stored on the recording surface;
(b) positioning the head adjacent a selected track on the recording surface;
(c) for each of the population of PES modes, sequentially generating a sequence of PES samples from the servo position data associated with the selected track;
(d) identifying an optimal PES mode from the population of PES modes in relation to linearity across a radial width of the selected track of the respective sequences of PES samples;
and, thereafter,
(e) using the optimal PES mode to generate a position error signal when the head is positioned adjacent the selected track.

3 more elements

Dependencies are inferred from the claim text.

Multi-mode servo position error signal demodulator circuit

Life of this patent

Multi-mode servo position error signal demodulator circuit

Life of this patent

Abstract

Claims17