Laser beam modulation apparatus

摘要

A laser beam modulation apparatus modulates a EFM (eight-fourteen modulated) signal to generate as a laser power control signal a pulse modulated EFM signal (PM-EFM). During each of on-time intervals of the EFM signal, the pulse modulated EFM signal serves to apply the laser beam on a recording area on a phase-change disk and to undulate the laser beam in order to prevent an overheating of the recording area.