| 摘要 |
PURPOSE:To obtain a tracking servo which ensures reproduction data can finally approximate to the maximum in every control area by dividing the area for controlling an electrostriction element into N-number of parts in the longitudinal direction of a track, controlling said element independently in said areas and calculating sequentially control data. CONSTITUTION:A head H is fitted at the top of the electrostriction element 2 such as a bimorph board, and the electrostriction element 1 is deviated by the prescribed amount with the aid of a control voltage supplied to said element 2. N-nuber of electrostriction control areas 1-64 (N is integer, for instance N=64) is set by approximately the same interval in the longitudinal direction of the track T, and the electrostriction element 2 is independently controlled at every control area. To control said element in such a way, the 1st memory 3 is provided, and at an address corresponding to each control area, the prescribed divided control voltage is stored. The envelope of a reproduction output is detected, and the digital data (for instance, data of eight bites) is converted by a detected output A/D converter 7. This reproduction data CD is supplied to an arithmetic unit 8 constituted of a microcomputer. |
