| 摘要 |
PCT No. PCT/EP86/00126 Sec. 371 Date Dec. 22, 1986 Sec. 102(e) Date Dec. 22, 1986 PCT Filed Mar. 8, 1986 PCT Pub. No. WO86/05308 PCT Pub. Date Sep. 12, 1986.An arrangement for obtaining precise scanning of audio and/or video disks with contactless scanning. A combination of coarse and fine drives serve to effect radial servo-readjustment. A radial error signal is applied to a comparator, so that when the radial error signal exceeds the threshold value set by the comparator, the coarse drive is driven with full operational voltage. The precision or fine drive has a control parameter which provides the radial error signal for operating the coarse drive. The comparator has a variable threshold for detecting the direction in which the coarse drive is to be driven.
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