Optical discs must be provided with a way of generating synchronization or clock information and tracking information if data is to be properly recorded and read. Conventionally, tracking information is provided throughout each block of each segment of a data track of an optical disc and the read beam of the optical drive is continuously monitoring the track to provide tracking information on a continuous basis. Continuous generation of information often causes the tracking servo feedback signal to be noisy due to the varying data pattern coexisting with the tracking data, often resulting in tracking errors.
An approach to providing a relatively noise free tracking information servo feedback signal is to provide clock information and tracking information in only a small portion, the synchro-servo zone, of each sector or data block, with the informational data being provided in the remainder of each block. With this approach, clock information and tracking information are provided only periodically and not at the time informational data is being read or recorded, whereby the signals generated are relatively free of noise. The generation of the tracking information servo feedback signal utilized in this approach is the subject of this invention.