PURPOSE: To detect precisely and reliablly a defect by deciding the existence of the defect when a dropout detecting period is reproduced in backward and a dropout is detected at the repeat of forward reproduction once or prescribed times.
CONSTITUTION: A disc 1 in which information signals into which address signals are inserted at prescribed intervals are recorded is reproduced by a reproducing stylus 6 of a reproducing device 10 and dropouts of the obtained information signals are detected by detecting circuits 13W15. The values of address signals supplied from the reproducing device 10 before the dropout detecting period are stored in a storage means, and after completing the detection, the reproducing device 10 is reproduced backward by a control means until the value of the address signal from the reproducing device 10 coincides with the address signal value of the storage means. Then, the forward reproduction is executed, and when a dropout is detected at the repeat of the forward reproduction once or prescribed times, the decision circuit decides the existence of a defect.
YOKOUCHI KENTAROU
YOSHIKAWA HIROYOSHI
