Patent ID: 8400727

Claim:
A recording device comprising: a recording medium comprising an intermediate pattern for self-servo writing, wherein the recording medium is configured to be driven and rotated, and wherein the intermediate pattern is configured as a multi-spiral pattern; an arm comprising an electromagnetic transducer, wherein the arm is configured to be rotated by a voice coil motor current supplied to a voice coil motor and wherein the arm is configured to position the electromagnetic transducer at a predetermined position on the recording medium; a positioning module configured to position the arm at a location at which the electromagnetic transducer detects a rotational synchronization component of the intermediate pattern; a self-servo write clock generator configured to generate a self-servo write clock based on the detected rotational synchronization component; and an on-track module configured to position the electromagnetic transducer at a self-servo write start location on the intermediate pattern, wherein the self-servo write start location serves as a position for starting self-servo write based on the generated self-servo write clock, wherein, until the on-track module completes the positioning, the self-servo write clock generator is further configured to: sequentially change a decoding gate interval corresponding to the intermediate pattern in accordance with the rotational synchronization component, and capture a spiral reproduction waveform, wherein the self-servo write clock generator comprises a decoding gate setting module configured to sequentially adjust the decoding gate interval corresponding to the intermediate pattern based on a correction value associated with the rotational synchronization component, and wherein the decoding gate setting module is further configured to use a sine wave function of a lower-order rotational synchronization component as the correction value.