Correcting tangential errors of optical head of disc system - determining static tangential errors and storing correction values in memory accessed for each radial position

摘要

An optical head unit (P) has a servo controlled mirror (SR) that provides adjustment of the scanning beam's tangential position error dependent upon correction values (K) held in a memory (M). The correction values are determined for each radial position as part of a calibration and setting process. In operation in the audio mode a selector (S11) connects the head to the audio processor (AP) coupled to a sub-code address unit (SA) to access the memory content for different radial locations. In the video mode the video processor is accessed and line synchronising and reference signals are accessed (LL, RV) and compared (PLL) to correct for time base errors. USE/ADVANTAGE - Reduced cost for optical scanning correction in combined audio and video players.