DISK DATA SIGNAL REPRODUCING CIRCUIT

PURPOSE:To improve the jitter margin. CONSTITUTION:In such a format that pits in an outer circumferential part of a disk become smaller in size against a rotary angle, e.g. a CAD format, etc., even when the pulse width indicating the existence of pit data of a pit data detecting signal to be outputted from an optical sensor in the outer circumferential part of the disk is narrowed, the pulse width indicating the existence of pit data of a binary signal obtained by binarizing the above signal should not be narrowed. The subject circuit is provided with a binary deciding value generating circuit 20 for making the size of a deciding value signal S4 indicating the existence of pit data smaller when the optical sensor 2 in a track position is in the outer circumferential part of the disk 1 than when it is in an inner circumferential part of the disk 1. Then, the binary signal S5 is obtained from a pit data detecting signal S2 by a binarization circuit 11 using this deciding value signal S4.