Position information modulation on servo track of DVD

摘要

A record carrier such as a writable DVD has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information at regular intervals. The modulated parts start with a bit sync element and are of a data type having a data bit element or of a word sync type having a word sync element. The bit sync element, word sync element and the data bit element being modulated according to the same predetermined type of modulation of the periodic variation. The distances between all elements constituting the modulated parts are unique. Modifications of known devices for reading and/or writing the record carrier with this modulation scheme are disclosed.