Eight-to-fourteen modulation (efm) signal generation in optical disk reproducing system using efm demodulated signal error correction flags

Abstract

An apparatus and method for generating an eight-to-fourteen modulation (EFM) signal in an optical disk reproducing system, capable of accurately generating the EFM signal regardless of the kinds of defects of a disk. The apparatus for generating an EFM signal from a radio frequency (RF) signal reproduced from an optical disk, includes a data slicing unit for selecting, in response to a selection signal, a first slice reference level generated by correcting the asymmetry of the RF signal, or a second slice reference signal generated using peak and bottom envelopes of the RF signal and the first slice reference level, to be a third slice reference level. The data slicing unit slices the RF signal based on the third slice reference level and outputs the slicing result as the EFM signal. A selection signal generating unit generates the selection signal in response to the number of occurrences of error correction flags or EFM flags. An EFM flag generating unit generates the EFM flags in accordance with bit pattern which is not used in demodulating the EFM signal. The error correction flags are generated in accordance with the amount of error which is present in the demodulated EFM signal.