Data read system of optical disk

Abstract

Abstract PURPOSE: To attain access to data blocks at random by optically scanning an optical disk in its radius direction at a constant speed, by separating and extracting a track signal from the read signal and then by detecting an unrecorded area. CONSTITUTION: As optical head 4 scans optical disk 1 in its radius direction, it crosses data blocks 2 and unrecorded area 3 to obtain reproduced signal 7. Then, this reproduced signal 7 is passed through LPF, etc., to separate and extract track signal 8. Time TB of the track separation part should be much less than time TA of the track part, and consequently unrecorded area 3 is detected by exercising a comparison supervision over times TA and TB to count the number of the areas. Since the number of unrecorded areas 3 and each data block bear corresponding relation, access to a desired data block can be attained at random by counting the number of them. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Hiroyasu Murakami

Bibliographic Details