Abstract: An optical disk device for writing information on an optical disk having an APC part for monitored driving of a laser diode is provided which performs first and second OPCs. An unused partition of a test area and reference power value are read out from the optical disk. APC is turned off if the recording speed exceeds 1×. A first optimum writing power value is obtained by writing on the unused partition by driving the laser diode at a plurality of first test laser power values centered on the reference power value and reading out the information. APC is turned on if the recording speed exceeds 1×. A second optimum writing power value is obtained by writing on a subsequent unused partition by driving the laser diode at a plurality of second test laser power values centered on the first optimum writing power value and reading out the information.

Abstract: An optical disk device for writing information on an optical disk having an APC part for monitored driving of a laser diode is provided which performs first and second OPCs. An unused partition of a test area and reference power value are read out from the optical disk. APC is turned off if the recording speed exceeds 1×. A first optimum writing power value is obtained by writing on the unused partition by driving the laser diode at a plurality of first test laser power values centered on the reference power value and reading out the information. APC is turned on if the recording speed exceeds 1×. A second optimum writing power value is obtained by writing on a subsequent unused partition by driving the laser diode at a plurality of second test laser power values centered on the first optimum writing power value and reading out the information.

Abstract: A CD encode device for a recordable optical disk includes a clock synthesizer multiplying, by M/N, a CD decode system clock, a clock having a frequency equal to 2n times or ½n times a frequency of the CD decode system clock, a clock obtained by the above multiplying functioning as a channel clock required during a write operation where M, N and n are respectively integers.