Patent ID: 6856586

Claim:
A recording clock generating device for recording data to an optical disk having a recording groove wobbled at a specific frequency in the radial direction, and prepits formed at a unit interval including a specific number of wobble periods, said device comprising: a wobble signal detector for detecting recording groove wobble and outputting a wobble signal; a period averaging arrangement for obtaining an average period for periods of the wobble signal; a timer for generating a rectangular wave with a period which is substantially equal to the average period obtained by the period averaging arrangement; a frequency multiplying PLL for multiplying timer output and generating a recording clock; and a phase difference measuring set for measuring a phase difference Z between the wobble signal and the rectangular wave; wherein the period averaging arrangement has a set for measuring a total time of N wobble signal periods, where N is a specific integer and holding the measured total time as a cumulative period V, and a set for measuring a next wobble period X, subtracting (1/N) of the cumulative period V from the cumulative period V, adding X to the resultant difference, correcting the measured phase difference Z, and using the resultant sum as a new total time for the N periods.