US Patent 7502287 Optical disk apparatus

An optical disk apparatus for recording data on an optical disk having a land pre-pit (LPP). An encoder of a DVD-R/RW drive records data while inserting synchronization information having a length of 14T at the top of a synchronous frame. The encoder sets synchronization information of the i-th frame (wherein i is an integer which is 0 or greater) and the (i+1)th frame of a plurality of consecutive frames to either a mark or a space such that each DSV is minimized. The encoder sets the synchronization information of the (i+2)th frame such that the polarity of the synchronization information of the (i+2)th frame is opposite to the polarity of the synchronization information of the i-th frame, and sets the synchronization information of (i+3)th frame such that the polarity of the synchronization information of (i+3)th frame is opposite to the polarity of the synchronization information of the (i+1)th frame. In this manner, the synchronization information of one of two frames, whether they are two odd frames or two even frames, is always set to a space.