US04907216Optical record carrier having position indentifying track modulation
AssigneeU.S. Philips Corporation
Assign./FiledMarch 6, 1990/ Dec. 9, 1987
InventorsRijnsburger; Johan M.
SummaryMethod for storing address information in a recordable disc's pregroove. Different from MDs modulated ADIP wobble however.
AbstractA system for recording and/or reading an information signal (V<SUB>i</SUB>) on an elongated track (4) of an optically readable record carrier (1). A position-identifying signal (V<SUB>p</SUB>) which is synchronous with a clock signal is recorded on the track 4 by modulating the transverse excursion of the track, the signal V<SUB>p</SUB> indicating the instantaneous position along the track at which the information signal V<SUB>i</SUB> is located. The frequency band of the position-identifying signal V<SUB>p</SUB> is situated substantially outside the frequency band of the information signal V<SUB>i</SUB>. In manufacturing such a record carrier, the deflection of a recording beam of radiation in a direction substantially transverse to the track is modulated by the position-information signal V<SUB>p</SUB>.