CONTROL SYSTEM FOR AN OPTICAL DATA RECORDING APPARATUS

摘要

Control system for an optical data recording apparatus. Disclosed is a closed loop control system for an optical recording apparatus of the read after write type comprising a comparator for comparing the input data signal with a playback signal derived from the read beam which trails the write beam and is modulated by the data pattern inscribed on the recording medium by the write beam. The error signal generated by the comparator is applied to a controller which varies the modulation of the read beam in dependence on the error signal, for example, by modifying the data signal used to drive the write beam modulator. In this way, the control system compensates for nonuniformities in the recording medium and the like so as to ensure that the pattern inscribed by the write beam accurately represents the data to be stored.