Turning the tracking problem sideways: servo tricks for DVD+RW clock generation

This work describes a write clock generation scheme for rewritable DVD which eliminates a major issue for drop-in compatibility with DVD-ROMs. In order to do this, several tricks from servo systems are employed to improve the write clock. Fundamentally, the method used is to colocate a high frequency clock reference next to the data using a wobble groove. A variety of methods are considered to compensate for read-back signal distortion caused by different laser powers during reading, erasing and writing of data. Finally, harmonic compensation can be added to the clock to eliminate the effects of eccentricity and spindle variations. The result is the ability to do bit accurate edits on rewritable DVD media