Optical disc recorder

摘要

An error detector circuit compares a value corresponding to a laser power supplied from a monitor diode of an optical pickup with a value representative of a target laser power, and outputs an error from the target value to a change-over switch. The change-over switch selects one of low-pass filters used for CAV recording and CLV recording. The low-pass filer used for CAV recording has a larger time constant than that of the low-pass filter used for CLV recording. The servo gain of a servo loop during the CAV recording is therefore set smaller than that of a servo loop during the CLV recording. A change in the laser power becomes gentle.