Digital data reproduction appts. for optical disc

摘要

Pits(3) and intermediate areas of track are coated with a reflecting layer and transparent protection for readout by a laser and linear photodetector array. A matrix combines the four outputs for serial multiplexing, digitising and demultiplexing. Digital samples are delayed by three periods of a clock, equalised and held for processing. - A decision level is produced for a level comparator and a phase comparator. Samples on both sides of the intersections of the data signal with the decision level are interpolated to measure the phase difference between the intersections and the channel clock.