MULTIHEAD RECORDING AND RETRIEVAL APPARATUS AND PROCEDURE FOR USE WITH SELF-TIMING OPTICAL LATHE OR PRE-FORMATTED DISCS

摘要

An optical drive to transfer data between a data carrier (10) and a data communication circuit is disclosed. The drive has a support to rotate said carrier about an axis and a plurality of optical head assemblies are disposed about the axis. Each of the head assemblies are radially adjustable relative to said axis to scan said carrier as it rotates. Each of said head assemblies has a clock recovery circuit associated therewith to obtain a clock signal for data processed by respective ones of the optical head assemblies. A plurality of data streams may be processed and their outputs combined to enhance the data recovery rate. The clock signals are derived from a timing track conjointly rotatable with the carrier and providing a clock signal correlated to the radial position of each of the heads. Each of the head assemblies includes a first head to read the timing track and a second head to interrogate the data carrier.