B are views showing the structure of wobbled grooves of an optical disk; [0019]FIGS. 2A and 2B are a graph and view, respectively, showing a wobbling signal and a groove wobble; [0020]FIGS. 3A and 3B are views showing the structure of wobbled grooves of another optical disk; [0021]FIG. 4 is a block diagram for explaining the data processing process of a recording apparatus; [0022]FIG. 5 is a view