FOCUS CONTROL DEVICE OF OPTICAL DISK

摘要

A focus error signal generator (11) is connected with an LPF (12) and said LPF (12) is connected with phased compensation circuit (13) and phase delayed compensation circuit (14) which is connected to the addition amplifier (15). The said addition amplifier is connected with the amplifier (16) connected to the power amplifier (17). The said power amplifier is connected to the focus operator (18). This organization as above mentioned transfers cut-off frequency of the focus servo system to high band frequency. Therefore, moving velocity of the focus operator is faster due to reduction of the focus error signal from direct current flowing on the focus operator, the servo band is wider and tuning the gain of the focus servo loop system is easier than the previous invention.