| 摘要 |
PROBLEM TO BE SOLVED: To precisely generate the time interval per bit of bar code data to be reproduced and the detection time of a synchronizing mark pattern by calculating the time interval of one bit of base code data corresponding to the measured rotational frequency of an optical disk based on time interval value information. SOLUTION: A rotational speed detector 6 outputs a pulse corresponding to the rotational speed of a spindle motor 5 to disk rotational frequency measuring parts 513 and 516. When detecting it by the disk rotational frequency measuring part 513 that an optical disk is rotated with a prescribed frequency, a one-bit time interval calculation part 514 reads out the time interval value of each pattern in a memory part 515 and indicates a time interval for decoding of each pattern. A bar code decoder 13 decodes bar code data by the indicated time interval value and the detection interval value of a symbol mark pattern indicated from a synchronizing mark pattern time interval calculation part 517. |
