PURPOSE: To improve the reliability of an optical recording and reproducing device by performing reproduction only when a laser beam follows a prescribed track normally through a track follow fault detecting means.
CONSTITUTION: A playback signal of a prescribed sector read out of a recording disk 11 by an optical head 12, once sent to an envelope detecting means 16 via an amplifier 13, is stored in sector data memories 15a and 15b through a pulse generating means 14. During reproduction, the playback signal sent to the detecting means 16 is supplied to an envelope fault detecting means 17 to detect the occurrence of a fault; when the signal is normal, a command ON is supplied to a gate 20 and the output of the memory 15a or 15b is passed through the gate 20 and then led out through a digital demodulating means 21 and an error detecting/correcting means 22 for a pairty check, etc., thereby improving the reliability of the optical recording and reproducing device. If a fault is detected by the detecting means 17, a normalizing means 18 controls track follow correction.
ARAI SHIGERU
MINAMI AKIRA
SHIBATA ITARU
OGAWA SEIYA
