Patent 7397750 was granted and assigned to TEAC on July, 2008 by the United States Patent and Trademark Office.
An optical disk apparatus for detecting synchronization signals of an optical disk. Marks and spaces are alternately arranged as synchronization signals of the optical disk. An encoding/decoding circuit of the optical disk apparatus utilizes a rule for alternately arranging synchronization signals, thereby verifying a detected synchronization signal. When the polarity of a synchronization signal detected from a preceding synchronization frame is a mark, the next synchronization signal is a space. When the polarity of a detected synchronization signal is a space, the signal is determined to be a correct synchronization signal.