GAIN CONTROLLER, GAIN CONTROLLING METHOD, INFORMATION REPRODUCTION DEVICE AND METHOD AND INFORMATION RECORDER AND INFORMATION RECORDING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a gain controller or the like that can record or reproduce information to/from an information recording medium similarly to the case with a conventional gain controller even when intensity of a reflected light beam from the information recording medium is extremely weak. SOLUTION: The information reproduction device S having preamplifiers 6-8 that adjust the gain of a reproduced RF signal Srf and a focus error signal Sfe generated based on light receiving signals Sa-Sf obtained by receiving a reflected light of a light beam B from an optical disk 1 is provided with an AND circuit 21 that detects whether or not the reproduced RF signal Srf and the focus error signal Sfe are generated and outputs a servo control start signal Sfok only when the reproduced RF signal Srf and the focus error signal Sfe are generated and with a CPU 18 that controls the preamplifiers 6-8 so as to increase the gain of the preamplifiers 6-8 by a prescribed value when no servo control start signal Sfok is outputted.