| 摘要 |
PROBLEM TO BE SOLVED: To avoid such troubles as sound jump and the requirement of much time for track search by reducing the level of a tracking error signal at a fixed rate according to a signal for adjusting tracking balance. SOLUTION: A tracking servo is turned off, a laser beam is reciprocated in the radial direction of an MD, and a tracking error signal TE with a fixed frequency is generated. A switch signal Ts is sent, switching elements S1 and S2 are turned on, and the level of E and F signals being inputted to variable amplifiers 31 and 32 is reduced, for example, by 4-6 dB. Then, tracking balance signals TBAL1 and TBAL2 are outputted for adjusting tracking balance so that the center potential of a tracking error signal TE coincides with preset reference potential. In the case of coincidence, the amplification factor of the variable amplifiers 31 and 32 is fixed. The switch signal Ts is cancelled for setting the level of the tracking error signal to an original one again, and the tracking servo is turned on.
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