A disc player wherein a single motor mounted on a chassis is coupled to a disc transport mechanism through a first power transmission system and to a pickup transport mechanism through a second power transmission system. The disc player comprises a pickup restraining mechanism for restraining the pickup from moving upon the pickup reaching one end of path of its travel where the pickup is to be re...

PURPOSE:To prevent the misdetecting action of an input buffer to an output noise at the time when output data change by providing a signal change detecting circuit and an input buffer threshold value control circuit. CONSTITUTION:When reading out '0' data, '0'-level clock pulse is outputted from a signal change detecting circuit R. This clock pulse is converted into a '1'-level clock pulse phiN th...