Patent ID: 6587422
Filing Date: 2003-07-01
Classification: G11B

Abstract:
A disk recording device capable of data writing onto a disk for overwriting, comprising:a clock reproduction circuit for reproducing a bit from recorded data read from the disk; an encoder for data processing to modulate input data into recording data suitable for recording onto the disk; and an optical head for reading recorded data from the disk, and for writing the recording data supplied from the encoder; wherein, for an overwriting operation, the optical head reads the recorded data from the disk, the clock reproduction circuits reproduces a bit clock from the recorded data read by the optical head, the encoder performs data processing in synchronism with the bit clock reproduced by the clock reproduction circuit to thereby prepare recording data which is in synchronism with the recorded data, and the optical head writes the recording data onto the disk based on an output from the encoder, wherein the optical head generates a main beam for recording onto the disk, and a preceding beam for tracing a signal track on the disk prior to the main beam, and detects a reflection beam of the preceding beam, reflected from the disk, and the clock reproduction circuit reproduces the bit clock based on a result of detection of the reflection beam of the preceding beam; and wherein the optical head includes a first light source for generating the main beam and a second light source which is different from the first light source, for generating the preceding beam.