| 摘要 |
<p>A device is described for scanning an information plane having tracks in which a track to be scanned is tracked by means of the three-beam method. Each one of the three beams is push-pull detected by three split detection systems (10, 11, 12). A position signal Ep which is a measure of the position of an adjustable element (9) in the device determining the transversal position of the spots with respect to the tracks is derived from the detector signals by means of a special electronic circuit (24-26, 30-32). A control circuit 33 can correct the position of the element by means of the position signal. A normalizing signal with which the position signal Ep is made independent of the intensity of the beams can also be derived from the same detector signals. <IMAGE></p> |
