| 摘要 |
PURPOSE:To prevent the titled device from being influenced by a high frequency resonance point and to ease the cost-down by sampling an error signal by a period corresponding to a resonance frequency of the high frequency resonance point, converting it successively to a digital signal, and thereafter, compensating the error signal by an arithmetic processing, converting it to an analog signal and generating a driving signal. CONSTITUTION:A sampling pulse outputted from a controlling circuit 21 is supplied to an A/D converter 20, and an output data of the A/D converter 20 is supplied to a digital filter 22 being a compensating means. The digital filter 22 is formed, for instance, so as to execute a lead phase compensation, and a data outputted from the digital filter 22 is supplied to a D/A converter 23 and converted to an analog signal. Said processing is executed by a period of a sampling frequency (fs) by the controlling circuit 21. An output of the D/A converter 23 is supplied to a driving coil 9 in a focus actuator through a focus actuator driving circuit 24, and an objective lens 6 in a pickup 1 is displaced in its optical axis direction.
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