| 摘要 |
The control signal generator(28) standardizes the mirror count signal of the mirror count circuit(24) and outputs it as a switching signal of the switching device(30). When the control signal of the control signal generator(28) is a low level, the switching device(30) performs tracking servo by outputting the phase compensated tracking error signal to the coil drive circuit(38), in case the control signal of the control signal generator(28) is a high level, completes the focusing servo of the focus error signal of the phase compensating circuit(18) by outputting the outputting signal of the 2nd drive signal generator(34) to the coil drive circuit(38). So, the focusing servo based on the output signal of the 2nd drive signal generator(34) is started and the beam spot returns to the objective track.
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