Optical disk device and integrated circuit used therein
AssigneeHitachi, Ltd.
InventorsAtsushi Kikugawa, Hiroyuki Minemura
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Abstract
This invention involves irradiating an optical disk with laser light, pulse-driven by a high-frequency signal from an HF oscillator, and converting the output of a photo-detector that receives laser light reflected from the optical disk into an electronic pulse readout signal using a current amplifier. The pulse readout signal is converted into a temporally continuous readout signal by a peak hold circuit. The invention solves the problems of SNR deterioration of the readout signal and the difficulty of removing the impact of high-frequency modulation accompanying the increase in the readout speed factor in optical disk devices.
Claims5
An optical disk drive, comprising:
- a high-frequency oscillator;
- a laser light source;
- a light source driver for pulse-driving said laser light source based on a clock generated as an output of said high-frequency oscillator;
- an optical system for irradiating an optical disk with laser light generated from said laser light source;
- a photo-detector for receiving said laser light reflected from said optical disk;
- means for converting an output of said photo-detector to an electronic pulse readout signal, wherein said electronic pulse readout signal is a product of a waveform of said output and a periodic high-frequency pulse train;
- and
- means for converting said electronic pulse readout signal to a temporally continuous stepwise readout signal, wherein each pulse of said electronic pulse readout signal operates in synchronization with said clock.
Dependencies are inferred from the claim text.