APPARATUS AND METHOD FOR CORRECTING ASYMMETRIC ERROR AND CLOCK RESTORATION DEVICE OF OPTICAL REPRODUCTION SYSTEM

摘要

PURPOSE: An apparatus and a method for correcting asymmetric error and a clock restoration device of an optical reproduction system are provided to correct distortion of an RF signal due to inter-symbol interference according to inaccurate pit length and land length when data is recorded in an optical recording medium. CONSTITUTION: An asymmetric error correcting apparatus includes a zero crossing detector(320), an asymmetric error detector(340), and a correction unit. The zero crossing detector sequentially extracts four samples from a digital signal input from an A/D converter and detects zero crossing from the center two samples. The asymmetric error detector judges if the digital signal is asymmetric or not and judges asymmetric polarity from the sum of the two samples of both sides of the four samples when the zero crossing is detected. The correction unit corrects the asymmetric error of the digital signal according to the detected asymmetric polarity.