Device for detecting position information from an optical record carrier

摘要

An optical record carrier ( 1 ) is provided with tracks having a groove ( 4 ) wobbled in a transverse direction and predetermined positions ( 18 ) along the track. The wobble comprises a substantially monotonous undulation ( 15 ). Local excursions ( 16 ) of the groove superposed on the undulation at the predetermined positions represent position information, such as addresses. The spatial frequency of the undulation is lower than that of the excursions.