Patent ID: 7460452
Filing Date: 2008-12-02
Classification: G11B

Abstract:
1. A restoration system, which optically picks up information from an optical disc and restores the information, the restoration system comprising: a slice which samples a signal optically picked up from the optical disc; a phase locked loop which receives a signal output from the slice and generates a channel clock signal; a latch circuit which receives the signal output from the slice and the channel clock signal, and outputs the signal output from the slice in response to the channel clock signal; a 3T correction circuit which receives the channel clock signal, the signal output from the slice, and the signal output from the latch circuit and outputs a signal in which 3T is corrected, wherein the 3T correction circuit comprises: an extension storage device, which stores the signal output from the latch circuit in a predetermined storage device in response to the channel clock signal of the phase locked loop, outputs a storage state, and outputs stored data in response to a signal output from an extension determiner; a length measuring device, which receives the storage state from the extension storage device, detects a period of a predetermine pulse of the storage state, the length measuring device measures periods of previous and next pulses respectively before and after the predetermined pulse signal, and outputs a current length of the predetermined pulse, a previous length of the previous pulse, and a next length of the next pulse according to a measurement of the periods; a phase detector, which measures a phase difference between the channel clock signal and the signal output from the slice and outputs, according to a measurement, a leading phase, which indicates a difference between the signal output from the slice and the channel clock signal when the predetermined pulse is enabled, a trail phase, which indicates a difference between the signal output from the slice and the channel clock signal when the next pulse is enabled, and a previous phase, which indicates a difference between the signal output from the slice and the channel clock signal when the previous pulse is enabled; and an extension determiner, which receives the current length, the previous length, the next length, the leading phase, the trail phase, and the previous phase and determines a need for a correction and a direction of the correction by: a demodulator which demodulates the signal output from the 3T correction circuit.